WO2009158201A1

WO2009158201A1 - Methods op fabricating crystalline organic semiconductive layers

Info

Publication number: WO2009158201A1
Application number: PCT/US2009/047006
Authority: WO
Inventors: Robert S. Clough; Scott M. Schnobrich
Original assignee: 3M Innovative Properties Company
Priority date: 2008-06-27
Filing date: 2009-06-11
Publication date: 2009-12-30

Abstract

Disclosed herein are methods of preparing a semiconductor device including the steps of: depositing at least one organic crystal on a surface; depositing a semiconductor crystal growth solution in contact with the at least one organic crystal, wherein the semiconductor crystal growth solution includes at least one solvent and dissolved organic semiconductor compound; and forming an organic semiconductive layer upon evaporation of the at least one solvent from the semiconductor crystal growth solution.

Description

METHODS OP FABRICATING CRYSTALLINE ORGANIC SEMICONDUCTIVE LAYERS

FIELD

The present disclosure relates to methods of growing organic semiconductive layers, methods of fabricating organic semiconductor devices, and layers and devices formed thereby.

BACKGROUND

The use of organic semiconductors to fabricate electronic devices, including devices such as thin film transistors (TFTs) offers many advantages. Included in these advantages is that of providing a lower cost than commonly used inorganic semiconductor technology. Part of this lower cost is due to the ability to apply the organic semiconductor by traditional solution coating techniques rather than costlier vacuum vapor deposition processes. Solution coating techniques also offer an advantage of being able to manufacture devices on flexible, plastic substrates. Methods of fabricating such organic semiconductor devices with improved electrical performance are always needed.

BRIEF SUMMARY

Disclosed herein are methods of preparing a semiconductor device including the steps of: depositing at least one organic crystal on a surface; depositing a semiconductor crystal growth solution in contact with the at least one organic crystal, wherein the semiconductor crystal growth solution includes at least one solvent and a dissolved organic semiconductor compound; and forming an organic semiconductive layer upon evaporation of the at least one solvent from the semiconductor crystal growth solution. Also disclosed are methods of making a thin film transistor on a substrate, the method including the steps of: forming a gate electrode on a substrate; forming a dielectric layer on the gate electrode; forming a source electrode on the dielectric layer; forming a drain electrode on the dielectric layer, wherein the source electrode and the drain electrode are separated from each other at an area; and forming an organic semiconductive layer, wherein the organic semiconductive layer is positioned at least in a portion of the area separating the source electrode and the drain electrode, and wherein the organic semiconductive layer contacts both the source electrode and the drain electrode, by depositing at least one organic crystal in at least a vicinity of the area separating the source electrode and the drain electrode; depositing a semiconductor crystal growth solution in contact with the at least one organic crystal, wherein the semiconductor crystal growth solution includes at least one solvent and a dissolved organic semiconductor compound; and forming an organic semiconductive layer upon evaporation of the at least one solvent from the semiconductor crystal growth solution.

Articles made using methods as disclosed and exemplified herein are also included.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be more completely understood in consideration of the following detailed description of various embodiments of the disclosure in connection with the accompanying drawings, in which:

The figures are not necessarily to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number.

Figures. IA and IB show a cross-sectional representation of two exemplary organic thin film transistors. Figures. 2A-2F are optical micrographs of a semiconductive layer grown as in

Example 1.

Figure 3 is an optical micrograph of organic crystals of an organic semiconductor compound deposited on a gate electrode dielectric from solution as in Example 2.

DETAILED DESCRIPTION

In the following description, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration several specific embodiments. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense.

All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein and are not meant to limit the scope of the present disclosure.

Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any smaller range within that range.

As used in this specification and the appended claims, the singular forms "a", "an", and "the" encompass embodiments having plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.

Disclosed herein are methods of preparing a semiconductor device that include depositing at least one organic crystal on a surface; depositing a semiconductor crystal growth solution in contact with the at least one organic crystal, wherein the semiconductor crystal growth solution includes at least one solvent, and a dissolved organic semiconductor compound; and forming an organic semiconductive layer upon evaporation of the at least one solvent from the semiconductor crystal growth solution. Disclosed herein is also a method that includes depositing at least one crystal of an organic semiconductor on a surface; depositing a semiconductor crystal growth solution in contact with the at least one crystal, wherein the semiconductor crystal growth solution includes at least one solvent, and dissolved organic semiconductor compound; and forming an organic semiconductive layer upon evaporation of the at least one solvent from the semiconductor crystal growth solution.

Methods as disclosed herein include the step of depositing at least one organic crystal on a surface. In an embodiment, the at least one organic crystal that is deposited on a surface causes the nucleation of organic semiconductor material present in the semiconductor crystal growth solution. The terms "semiconductor material" and "semiconductor compound" are used interchangeably. The at least one organic crystal can therefore be referred to as a nucleating compound. The at least one organic crystal that is deposited on the surface can be any material that once deposited will cause the nucleation and growth of crystals of the organic semiconductor compound that is dissolved in the crystal growth solution. In an embodiment where the deposited organic crystal and the organic semiconductor compound in the semiconductor crystal growth solution are not the same, the at least one organic crystal generally does not have an unacceptably detrimental effect on the electrical properties of the final semiconductive layer that is formed using a method as disclosed herein. In an embodiment, the at least one organic crystal that is deposited on the surface has a chemical structure that is similar to the chemical structure of the organic semiconductor compound in the semiconductor crystal growth solution. In an embodiment, the at least one organic crystal that is deposited on the surface has a crystal structure that is similar to the crystal structure of the organic semiconductor compound in the semiconductor crystal growth solution. Organic semiconductor compounds as are commonly utilized by one of skill in the art may be utilized herein as the at least one organic crystal. In an embodiment the deposited organic crystal, the organic semiconductor material in the semiconductor crystal growth solution, or both, may have a polyacene backbone. Exemplary organic semiconductor compounds include, but are not limited to polyacenes, heteroacenes, perylenes, olgiothiophenes, phthalocyanines and buckminsterfullerenes functionalized with organic groups. Polyacenes that may be utilized include, but are not limited to, anthracene, tetracene (naphthacene), pentacene, hexacene, heptacene, nanoacene and derivatives thereof for example.

Derivatives of polyacenes may also be utilized. Derivatives that include functional groups such as aliphatic hydrocarbons (alkyls, alkenyls, and alkynyls, etc.), aromatic hydrocarbons (phenyl, naphthyl, etc.), alkoxyls, halogens, acyls (benzoyl, etc.), esters, ethers, aminos, hydroxyl, amides, cyanos, silyls, photoreactive groups or combinations of two or more of these functional groups (benzyls, etc.) may be utilized. Quinone derivatives of polyacenes may also be used. One or more hydrogen atoms on one or more of the aromatic rings of a polyacene may be replaced by the functional groups mentioned above or others. If two or more hydrogen atoms are replaced by such functional groups, these functional groups may be identical or different from each other. In an embodiment, the deposited organic crystal, the organic semiconductor material in the semiconductor crystal growth solution, or both, may be a compound according to Formula I below:

Formula I wherein each of Ri, R₂, R3, R₄, R5, R₆, R₇, Rs, R9, Rio, Rn, and Ri₂ may each independently be hydrogen; a substituted or unsubstituted C1-C40 alkyl or alkenyl group that can be cyclic, linear, branched or a combination thereof; a substituted or unsubstituted C1-C40 alkoxy group; a substituted or unsubstituted C₆-C₄O aryloxy group; a substituted or unsubstituted C₁-C₄₀ carbonyl group; a substituted or unsubstituted C₂-C_4O alkoxycarbonyl group; a substituted or unsubstituted C7-C40 aryloxycarbonyl group; a substituted or unsubstituted C₂-C₄O alkylcarbonyloxy group; a substituted or unsubstituted C7-C40 arylcarbonyloxy group; a substituted or unsubstituted amino carbonyl group (-C(=O)NR_aR_b wherein R_a and R_b are independently a hydrogen, or a substituted or unsubstituted hydrocarbyl group); a halogen; a cyano group; a nitro group; a substituted or unsubstituted heterocyclic ring comprising at least one of O, N, S, and Se in the ring; a substituted or unsubstituted silyl group; or a substituted or unsubstituted silylalkynyl group; and wherein independently each pair of R₂ and R₃ and/or R₈ and R₉, may be cross- bridged to form a C4-C40 saturated or unsaturated ring, which saturated or unsaturated ring may be intervened by O, S, Se, or N(R_a) where R_a is defined as above; and wherein n is 0, 1, 2, 3, or 4. In some embodiments, at least one of the R₁, R₂, R3, R₄, R5, R₆, R7, Rs, R9, Rio, R₁₁, and Ri₂ is a silylalkynyl group such as a silylethynyl group of formula -C≡C-Si(Ri₅)(Ri₆)(Ri7) where Ri₅, Ri₆, and Ri₇ are defined below. Exemplary silylethynyl groups include, but are not limited to, trialkylsilylethynyl groups, dialkylalkenylsilylethynyl groups, and dialkenylalkylsilylethynyl groups.

For the above-described groups that can be substituted, any suitable substituent can be used. Suitable substituents often include, but are not limited to, halogens, hydroxyl groups, alkyl groups, cyano groups, amino groups, carbonyl groups, alkoxy groups, thioalkoxy groups, nitro groups, carboxylic acid groups, carboxylic ester groups, alkenyl groups, alkynyl groups, aryl groups, heteroaryl groups, or combinations thereof. Exemplary combinations thereof include halogenated alkyl groups or halogenated alkoxy groups.

In an embodiment the deposited organic crystal, the organic semiconductor material in the semiconductor crystal growth solution, or both, may have a pentacene backbone. In an embodiment, the deposited organic crystal, the organic semiconductor material in the semiconductor crystal growth solution, or both, may be a compound according to Formula II below:

Formula II wherein each of Ri, R₂, R3, R₄, Rs, R9, Rio, Rn, R15, Ri6, and Rn may each independently be hydrogen; a substituted or unsubstituted C1-C40 alkyl or alkenyl group that can be cyclic, linear, branched or a combination thereof; a substituted or unsubstituted Ci-C₄₀ alkoxy group; a substituted or unsubstituted C₆-C₄O aryloxy group; a substituted or unsubstituted C1-C40 carbonyl group; a substituted or unsubstituted C2-C40 alkoxycarbonyl group; a substituted or unsubstituted C7-C40 aryloxycarbonyl group; a substituted or unsubstituted C₂-C_4O alkylcarbonyloxy group; a substituted or unsubstituted C₇-C₄₀ arylcarbonyloxy group; a substituted or unsubstituted amino carbonyl group (-C(=O)NR_aRb wherein R_a and Rb are independently a hydrogen or a substituted or unsubstituted hydrocarbyl group); a halogen; a cyano group; a nitro group; a substituted or unsubstituted heterocyclic ring comprising at least one of O, N, S, and Se in the ring; a substituted or unsubstituted silyl group; or a substituted or unsubstituted silylalkynyl group; and wherein independently each pair of R₂ and R3 and/or R₉ and Rio, may be cross- bridged to form a C4-C40 saturated or unsaturated ring, which saturated or unsaturated ring may be intervened by O, S, Se, or N(R_a) where R_a is defined as above; and wherein A represents silicon or germanium. In some embodiments, the group -A(Ri₅)(Ri₆)(Ri₇) is a trialkylsilyl, dialkylalkenylsilyl, or dialkenylalkylsilyl.

In an embodiment, 6,13-bis(triisopropylsilylethynyl)pentacene (referred to herein as "TIPS") may be used as the organic crystal, the semiconductor material in the semiconductor crystal growth solution, or both. Specific methods of making TIPS and other relevant information regarding TIPS may be found in U.S. Patent No. 6,690,029 (Anthony, et al).

In some embodiments, the deposited organic crystal, the organic semiconductor material in the semiconductor crystal growth solution, or both, may be a compound according to of Formula III below.

Formula III

In some embodiments of Formula III, each R independently comprises (i) a branched or unbranched, substituted or unsubstituted alkyl group, (ii) a substituted or unsubstituted cycloalkyl group, or (iii) a substituted or unsubstituted cycloalkylalkylene group. Each R' independently comprises (i) a branched or unbranched, substituted or unsubstituted alkenyl group, (ii) a substituted or unsubstituted cycloalkyl group, or (iii) a substituted or unsubstituted cycloalkylalkylene group. Each R" comprises (i) hydrogen, (ii) a branched or unbranched, substituted or unsubstituted alkynyl group, (iii) a substituted or unsubstituted cycloalkyl group, (iv) a substituted or unsubstituted cycloalkylalkylene group, (v) a substituted aryl group, (vi) a substituted or unsubstituted arylalkylene group, (vii) an acetyl group, or (viii) a substituted or unsubstituted heterocyclic ring comprising at least one of O, N, S and Se in the ring. The variable x is equal to 1 or 2; the variable y is equal to 1 or 2; the variable z is equal to 0 or 1, and the sum (x + y + z) is equal to 3. Each X independently comprises (i) hydrogen, (ii) a halogen, (iii) a branched or unbranched, substituted or unsubstituted alkyl group, (iv) a substituted or unsubstituted aryl group, (v) a branched or unbranched, substituted or unsubstituted alkenyl group, (vi) a branched or unbranched, substituted or unsubstituted alkynyl group, (vii) a substituted or unsubstituted heterocyclic group, (viii) a cyano group, (iv) an ether group, (x) a branched or unbranched, substituted or unsubstituted alkoxy group, (xi) a nitro group, or (xii) any two adjacent X groups combine to form (a) a substituted or unsubstituted carbocyclic ring or (b) a substituted or unsubstituted heterocyclic ring. In some examples, the groups Rx, Ry, Rz, or combinations thereof can be substituted with one or more fluoro groups. Examples of semiconductor materials include, but are not limited to, 6,13-bis(allyldiisopropylsilylethynyl)pentacene, 6,13- bis(isopropenyldiisopropylsilylethynyl)pentacene, 6, 13-bis(cyclopropyldiisopropyl- silylethynyl)pentacene, 6, 13-bis(l -methylenepropyldiisopropylsilylethynyl)pentacene,

6, 13-bis(cyclopropyldiisopropylsilylethynyl)-l -fluoro-pentacene, 6,13- bis(cyclopropyldiisopropylsilylethynyl)-2.9(10)-difluoro-pentacene, 6,13- bis(cyclopropyldiisopropylsilylethynyl)- 1,8(11 )-difluoro-pentacene, 6,13- bis(cyclopropyldiisopropylsilylethynyl)-2,3,9,10-tetramethylpentacene, 6,13- bis(cyclopropyldiisopropylsilylethynyl)-2,3 :9, 10-bis(c-dihydrofurano)pentacene, 6,13- bis(allyldicyclopropylsilylethynyl)pentacene, 6,13-bis((2-methyl-l,3- dithiane)diisopropylsilylethynyl)pentacene, and 6, 13-bis(diisopropenylisopropylsilylethynyl)pentacene.

In other embodiments of Formula III, each R, R' and R" independently comprises (i) hydrogen, (ii) a branched or unbranched, substituted or unsubstituted alkyl group, (iii) a branched or unbranched, substituted or unsubstituted alkenyl group, (iv) a substituted or unsubstituted cycloalkyl group, (v) a substituted or unsubstituted cycloalkylalkylene group, (vi) a branched or unbranched, substituted or unsubstituted alkynyl group, (vii) a substituted or unsubstituted aryl group, (viii) a substituted or unsubstituted arylalkylene group, (ix) an acetyl group, (x) a substituted or unsubstituted heterocyclic ring comprising at least one of O, N, S and Se in the ring, (xi) a substituted or unsubstituted ether group or polyether group, or (xii) a substituted or unsubstituted sulfonamide group. At least one R, R' or R" comprises a fluorinated monovalent radical comprising one or more fluorine atoms with said one or more fluorine atoms being separated from either silicon atom by at least three atoms or four covalent bonds. The variables x, y and z each independently equal 0, 1, 2 or 3 and the sum (x + y + z) is equal to 3. Each X independently comprises (i) hydrogen, (ii) a halogen, (iii) a branched or unbranched, substituted or unsubstituted alkyl group, (iv) a substituted or unsubstituted aryl group, (v) a branched or unbranched, substituted or unsubstituted alkenyl group, (vi) a branched or unbranched, substituted or unsubstituted alkynyl group, (vii) a cyano group, (viii) a nitro group, (ix) a branched or unbranched, substituted or unsubstituted alkoxy group, or (x) any two adjacent X groups combine to form (a) a substituted or unsubstituted carbocyclic ring or (b) a substituted or unsubstituted heterocyclic ring. Examples of semiconductor materials include, but are not limited to, 6,13-bis(3,3,3-trifluoropropyldiisopropylsilylethynyl)pentacene, 6,13- bis(3,3,4,4,5,5,6,6,6-nonafluorohexyldimethylsilylethynyl)pentacene, 6,13- bis(3,3,4,4,5,5,6,6,6-nonafluorohexyldiisopropylsilylethynyl)pentacene, 6,13- bis(3, 3,4,4,5,5, 6,6, 7,7, 8, 8, δ-tridecafluorooctyldimethylsilylethyny^pentacene, 6,13- bis(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafiuoro- decyldiisopropylsilylethynyl)pentacene, and 6,13-bis-((3- heptafluoroisopropoxy)propyldiisopropylsilylethynyl)pentacene.

In an embodiment, the deposited organic crystal, the organic semiconductor material in the semiconductor crystal growth solution, or both, may be a compound according to Formula IV below:

Formula IV wherein each of R₂, R3, R7, Rs, R15, Ri6, and Ri₇ may each independently be hydrogen; a substituted or unsubstituted C1-C40 alkyl or alkenyl group that can be cyclic, linear, branched or a combination thereof; a substituted or unsubstituted C1-C40 alkoxy group; a substituted or unsubstituted C₆-C₄₀ aryloxy group; a substituted or unsubstituted Ci-C₄₀ carbonyl group; a substituted or unsubstituted C₂-C₄₀ alkoxycarbonyl group; a substituted or unsubstituted C₇-C₄₀ aryloxycarbonyl group; a substituted or unsubstituted C₂-C₄₀ alkylcarbonyloxy group; a substituted or unsubstituted C₇-C₄₀ arylcarbonyloxy group; a substituted or unsubstituted amino carbonyl group (-C(=O)NR_aR_b wherein R_a and R_b are independently a hydrogen or a substituted or unsubstituted hydrocarbyl group); a halogen; a cyano group; a nitro group; a substituted or unsubstituted heterocyclic ring comprising at least one of O, N, S, and Se in the ring; a substituted or unsubstituted silyl group; or a substituted or unsubstituted silylalkynyl group; and wherein independently each pair of R₂ and R3 and/or R₇ and Rs, may be cross-bridged to form a C₄-C₄₀ saturated or unsaturated ring, which saturated or unsaturated ring may be intervened by O, S, Se, or N(R_a) where Ra is defined as above; and wherein A represents silicon or germanium. In some embodiments, the group -A(Ri₅)(Ri₆)(Ri₇) is a trialkylsilyl, dialkylalkenylsilyl, or dialkenylalkylsilyl.

The at least one organic crystal is deposited on a surface. The area where the at least one organic crystal is deposited is generally the area on the surface where the organic semiconductive layer is ultimately to be formed. The at least one organic crystal can be deposited only in the area where the organic semiconductive layer is desired to be formed, or the at least one organic crystal can be deposited in an area that is more extensive than the area where the organic semiconductive layer is desired to be formed. If the area is larger than the extent of the desired organic semiconductive layer, further processing can but need not be carried out to remove the organic semiconductive layer once formed, in the areas where it is not necessary or desired.

The surface upon which the at least one organic crystal is deposited can be any surface on which one of skill in the art desires to from an organic semiconductive layer. In an embodiment, the surface can be a portion of a device that has already been formed, or can be a substrate upon which no structures or layers have previously been deposited. Although it is referred to as a surface, the surface need not be planar or flat. The at least one organic crystal (whether the same or a different material than the organic semiconductor in the crystal growth solution) can be deposited by any method known to one of skill in the art. In an embodiment, the step of depositing at least one organic crystal on the surface can be carried out before the step of depositing a semiconductor crystal growth solution. In an embodiment, the step of depositing at least one organic crystal can be carried out while the semiconductor crystal growth solution is being deposited. Details regarding depositing the at least one organic crystal before the semiconductor crystal growth solution will be discussed in the immediately following paragraphs and details regarding depositing the at least one organic crystal while depositing the semiconductor crystal growth solution will be discussed below.

Embodiments where the at least one organic crystal is deposited on the surface before the semiconductor crystal growth solution is deposited thereon can be carried out in different ways. In an embodiment, the at least one organic crystal can be formed directly on the surface. This can be accomplished by vapor depositing the at least one organic crystal on the surface. One of skill in the art, having read this specification, would understand how to deposit at least one organic crystal of a compound, for example, an organic semiconductor compound on the surface via vapor deposition. U.S. Patent No. 6,433,359 includes details regarding vapor deposition of pentacene, and is incorporated herein by reference. Forming the at least one organic crystal directly on the surface can also be accomplished by applying a solution to the surface, referred to herein as a nucleating solution, from which the at least one organic crystal will form. In an embodiment, the nucleating solution can be more dilute than the semiconductor crystal growth solution that will be discussed below. In an embodiment, a nucleating solution can include at least one solvent and at least one nucleating compound, which will form the at least one organic crystal when the at least one solvent is evaporated. The solvent in the nucleating solution can generally be any solvent in which the nucleating compound is at least somewhat soluble. In an embodiment, the nucleating solution can include less than about 2% by weight of the nucleating compound. In another embodiment, the at least one organic crystal can be formed and subsequently placed on the surface. In an embodiment, this can be accomplished for example by forming the at least one organic crystal at a first location and physically moving the organic crystals, for example via electrostatic methods to the surface. The organic crystals can be processed in order to affect the size of the organic crystals. For example, if the organic crystals are to be made smaller, physical processing steps can be carried out to break the at least one organic crystal. Physical processing steps can include grinding, milling, or sieving to remove organic crystals of a certain size. In another embodiment, forming and subsequently placing the crystals can also be accomplished by suspending the at least one organic crystal in a dispersion and then applying the dispersion to the surface. It is noted that in such an embodiment, the liquid portion of the dispersion is one in which the at least one organic crystal is generally not soluble. The organic crystals within the dispersion can be processed in order to affect the size of the organic crystals. For example, if the organic crystals are to be made smaller, physical processing steps can be carried out to break the at least one organic crystal. Physical processing steps can include physically shaking the dispersion, subjecting the dispersion to ultrasound radiation, or filtering the dispersion to remove organic crystals of a certain size. In embodiments where the at least one organic crystal is deposited on the surface before the semiconductor crystal growth solution is deposited thereon, the density at which the at least one organic crystal is deposited can be high enough so that at least one organic crystal exists in the general area of the surface where the organic semiconductive layer is ultimately desired. In an embodiment, the density at which the at least one organic crystal is deposited is not so high that too many organic crystals exist in the general area of the surface where the organic semiconductive layer is ultimately desired. In theory, an organic semiconductor device that has only one perfectly formed crystal as the semiconductive layer would be able to achieve the highest efficiency due to a lack of grain boundaries when compared to multiple crystalline domains. Therefore, the density at which the at least one organic crystal is deposited is a tradeoff between the perfect efficiency of a single crystal and the practicality of forming a semiconductive layer across the relevant portion of the surface.

In an embodiment, the at least one organic crystal is deposited at least on or near the location at which the organic semiconductive layer (or layers, if more than one semiconductive layer is being formed simultaneously) is to be formed. In an embodiment where TFTs are being made on a larger substrate, for example, the at least one organic crystal can be deposited at least at or near the area between multiple source and drain electrodes, i.e. at or near multiple channels. In an embodiment where TFTs are being made on a larger substrate, for example, a separate organic crystal can be deposited at least at or near the area between each source and drain electrode.

In other embodiments, the at least one organic crystal can be deposited while the semiconductor crystal growth solution is being deposited. Details regarding the semiconductor crystal growth solution utilized in such an embodiment and the deposition thereof will be discussed below (after the discussion of the semiconductor crystal growth solution generally).

Methods as disclosed herein also include deposition of a semiconductor crystal growth solution on the surface. The semiconductor crystal growth solution can be deposited in the same general area where the at least one organic crystal was deposited. In an embodiment, at least a portion of the semiconductor crystal growth solution is deposited to be in contact with the at least one organic crystal. In an embodiment, at least some of the semiconductor crystal growth solution is in contact with at the least one organic crystal.

The semiconductor crystal growth solution can be deposited only in the area where the semiconductive layer is to be formed, or can be deposited in an area that is larger than the area where the semiconductive layer is to be formed. The semiconductor crystal growth solution can be deposited by any method known to those of skill in the art. For example, the semiconductor crystal growth solution can be placed on the surface via liquid handling techniques; the semiconductor crystal growth solution can be spray coated, dip coated, knife coated, roll coated, gravure coated, inkjet printed, flexographic printed, or micropipetted on the surface. In the case where multiple TFT's are desired on a substrate, the semiconductor crystal growth solution can cover all the substrate or be placed on the substrate in smaller quantities that encompass individual TFT's and their nearest deposited crystal.

The semiconductor crystal growth solution generally includes at least one solvent, and dissolved organic semiconductor compound. The dissolved organic semiconductor compound that is present in the semiconductor crystal growth solution can be, but need not be the same compound as the at least one organic crystal that is or was deposited on the surface. In an embodiment, the dissolved organic semiconductor compound that is in the semiconductor crystal growth solution is the same compound as the at least one organic crystal that is deposited on the surface. In an embodiment, the semiconductor crystal growth solution contains dissolved organic semiconductor material and a different compound is deposited, as at least one organic crystal, on the surface. In both of these embodiments, the organic semiconductor material that is dissolved in the semiconductor crystal growth solution is the material which will ultimately form the bulk of the semiconductor in the organic semiconductive layer.

Compounds that can be utilized as the organic semiconductor material in the semiconductor crystal growth solution are the same materials as those discussed above as possible materials for the at least one organic crystal and are semiconductive. In an embodiment where the at least one organic crystal is a different compound than the organic semiconductor compound in the semiconductor crystal growth solution, the at least one organic crystal need not, but can, have semiconductive properties.

In an embodiment, the organic semiconductor compound in the semiconductor crystal growth solution is a polyacene compound (as discussed above). In an embodiment, the organic semiconductor compound in the semiconductor crystal growth solution has a structure as seen in formula I above. In an embodiment, the organic semiconductor compound in the semiconductor crystal growth solution has a structure as seen in formula II, III, or IV above. In an embodiment, the organic semiconductor compound in the semiconductor crystal growth solution has a structure as seen in formula III above. In an embodiment, the organic semiconductor compound in the semiconductor crystal growth solution has a structure as seen in formula II or formula IV above, wherein A is silicon. For example, the group -A(Ri5)(Ri6)(Ri7) in formula II or in formula III can be a trialkylsilyl, dialkylalkenylsilyl, or dialkenylalkylsilyl. In an embodiment, the organic semiconductor compound in the semiconductor crystal growth solution is a pentacene compound (as discussed above). In an embodiment, the organic semiconductor compound in the semiconductor crystal growth solution is a polyacene with at least one unsubstituted or substituted silyl groups; or an unsubstituted or substituted silylalkynyl groups. For example, the organic semiconductor compound includes at least one silylalkynyl group such as a silylethynyl group of formula -C≡C-Si(Ri₅)(Ri₆)(Ri₇) attached to a polyacene where R15, Ri₆, and Rn are defined above. Some organic semiconductor compounds include two silylethynyl groups attached to the polyacene. The silylethynyl group is often a trialkylsilylethynyl, dialkylalkenylsilylethynyl, or dialkenylalkylsilylethynyl group. The alkyl and alkenyl groups attached to the silylethynyl group can be linear, cyclic, branched, or a combination thereof. The alkyl and alkenyl groups can have up to 18 carbon atoms, up to 10 carbon atoms, up to 6 carbon atoms, up to 4 carbon atoms, or up to 3 carbon atoms. The alkyl and alkenyl groups can be substituted or unsubstituted with various substituent groups such as, for example, one or more fluoro groups. In an embodiment, the organic semiconductor compound in the crystal growth solution is 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS), 6,13- bis(allyldiisopropylsilylethynyl) pentacene, 6, 13-bis(isopropenyldiisopropylsilylethynyl) pentacene, 6, 13-bis(cyclopropyldiisopropylsilylethynyl)pentacene, 6, 13 -bis(l -methylene propyldiisopropylsilylethynyl)pentacene, 6, 13-bis(diisopropenylisopropylsilyl ethynyl)pentacene, and 6,13-bis(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10,10- heptadecafluorodiisopropylsilylethynyl)pentacene for example.

The semiconductor crystal growth solution also includes at least one solvent. Embodiments of semiconductor crystal growth solutions can include one solvent, or a mixture of more than one solvent. In an embodiment, the at least one solvent is advantageously a solvent in which the organic semiconductor material is at least somewhat soluble. In an embodiment, the organic semiconductor compound is soluble in an amount equal to at least about 0.5 wt-% in the at least one solvent. In another embodiment, the organic semiconductor compound is soluble in an amount equal to at least about 1 wt-% in the at least one solvent. In another embodiment, the organic semiconductor compound is soluble in an amount equal to at least about 5 wt-% in the at least one solvent.

In an embodiment, the at least one solvent is a halogenated aromatic hydrocarbon, a halogenated aliphatic hydrocarbon, an aromatic hydrocarbon, an ester, a carbonate, a ketone, an ether, a cyclic alkane, or a fluorinated solvent. In an embodiment, the at least one solvent is an aromatic hydrocarbon. Exemplary aromatic hydrocarbons include benzene, toluene, xylene, mesitylene, n-butylbenzene and tetrahydronaphthalene. In an embodiment, the at least one solvent is a halogenated aromatic hydrocarbon. Exemplary halogenated aromatic hydrocarbons include, but are not limited to, chlorobenzene, and dichlorobenzene. In an embodiment, the at least one solvent is a halogenated aliphatic hydrocarbon. Exemplary halogenated aliphatic hydrocarbons include, but are not limited to dichloromethane, chloroform, trichloroethane and trichloroethylene. In an embodiment, the at least one solvent is an ester. Exemplary esters include, but are not limited to, ethyl acetate, γ-butyrolactone and propiolactone. In an embodiment, the at least one solvent is a carbonate compound. Exemplary carbonate compounds, include but are not limited to, dimethyl carbonate, diethyl carbonate, methylethyl carbonate, propylene carbonate and butylene carbonate. In an embodiment, the at least one solvent is a ketone. Exemplary ketone compounds include, but are not limited to, methyl ethyl ketone and cyclohexanone. In an embodiment, the at least one solvent is an ether. Exemplary ether compounds include, but are not limited to, tetrahydrofuran and anisole. In an embodiment, the at least one solvent is a cyclic alkane. Exemplary cyclic alkane compounds include, but are not limited to, cyclohexane. In an embodiment, the at least one solvent is a fluorinated solvent. Exemplary fluorinated solvents include, but are not limited to, 1,3- bis(trifluoromethyl)benzene and 3-(trifluoromethyl)anisole.

Exemplary solvents and solvent systems can include (i) an alkane having 6 to 16 carbon atoms present in an amount in a range of 1 to 20 weight percent based on a weight of the solvent mixture and (ii) an aromatic compound of Formula (V) present in an amount in a range of 80 to 99 weight percent based on the weight of the solvent mixture.

(V)

In Formula (V), the group R^a is an alkyl, a heteroalkyl, an alkoxy, a heteroalkoxy, or a fused 5 or 6 member ring. Each group R^b is independently selected from an alkyl, an alkoxy, or a halo. The variable n is an integer in the range of 0 to 5. The amount of the organic semiconductor material dissolved in the solvent mixture is equal to at least 0.1 weight percent based on a total weight of the composition. Some specific combinations include an aromatic compound of Formula (V) selected from anisole, 3,5-dimethylanisole, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, isobutylbenzene, isopropyltoluene, n-propylbenzene, isopropylbenzene, mesitylene, tetrahydronaphthalene, or a mixture thereof. Some specific alkanes have 9 to 13 carbon atoms, 9 to 12 carbon atoms, 9 to 11 carbon atoms, or 10 to 12 carbon atoms.

A semiconductor crystal growth solution utilized herein can also include at least one binder. In an embodiment, the binder functions to provide mechanical integrity to a layer formed from the semiconductor crystal growth solution after evaporation of the solvent, i.e. the semiconductive layer. The binder can also function to affect the viscosity of the semiconductor crystal growth solution. The binder can render the semiconductor crystal growth solution capable of forming a film. In an embodiment, the binder can render the semiconductor crystal growth solution capable of forming a film and enhance the ability to coat or apply the solution. The binder, which in one embodiment is a polymer, may be an insulating binder, a semiconducting binder, or mixtures thereof. Examples of binders that can be utilized herein include, but are not limited to polystyrene, poly (α-methylstyrene), poly(α -vinylnaphthalene), poly(vinyltoluene), polyethylene, cis-polybutadiene, polypropylene, polyisoprene, poly(4-methyl-l-pentene), poly(4-methylstyrene), poly(chorotrifluoroethylene), poly(2-methyl-l, 3-butadiene), poly(p-xylylene), poly(pentafluorostyrene), poly(α -α -α '-α ' tetrafluoro-p-xylylene), poly[l, 1 -(2 -methyl propane) bis (4-phenyl) carbonate], poly(cyclohexyl methacrylate), poly(chlorostyrene), poly(2, 6-dimethyl-l, 4-phenylene ether), polyisobutylene, poly(vinyl cyclohexane), poly(vinylcinnamate), poly(4-vinylbiphenyl), poly(l,2-butadiene), polyphenylene, poly(methyl methacrylate), and polyvinyl phenol.

Copolymers of the above materials, or others can also be utilized. For example, a binder can include polymers of styrene and α -methyl styrene; copolymers including styrene, α -methylstyrene and butadiene, for example. In an embodiment, polystyrene is utilized as a binder. Both random or block copolymers can be used. Exemplary copolymers include, but are not limited to, poly (ethylene/tetrafluoroethylene); poly(ethylene/chlorotrifluoro-ethylene); fluorinated ethylene/propylene copolymer; polystyrene-co- α -methylstyrene; ethylene/ethyl acrylate copolymer; poly (styrene/10% butadiene); poly (styrene/15% butadiene); poly (styrene/2, 4 dimethylstyrene); cyclic olefin copolymers such as those commercially available from Dow Chemical under the trade designation TOPAS (all grades); branched or non-branched polystyrene-block- polybutadiene; polystyrene-block (polyethylene-ran-butylene)-block-polystyrene; polystyrene-block-polybutadiene-block-polystyrene; polystyrene- (ethylene-propylene)- diblock-copolymers (e. g. KRATON-G 170 IE, Kraton Polymers U.S. LLC, Houston, TX); poly(propylene-co-ethylene); and poly (styrene-co-methylmethacrylate). The amount of organic semiconductor compound in the semiconductor crystal growth solution is generally dictated at least in part by the solubility of the organic semiconductor compound in the at least one solvent (in combination with other components of the semiconductor crystal growth solution). In an embodiment, the semiconductor crystal growth solution is a saturated solution of the organic semiconductor material. One of skill in the art will know, having read this specification, how to prepare a semiconductor crystal growth solution that is saturated. In an embodiment, the semiconductor crystal growth solution is not saturated with the organic semiconductor material. In an embodiment where the organic semiconductor compound is a polyacene compound, a semiconductor crystal growth solution can include from about 0.1 wt-% to about 25 wt-% of the organic semiconductor compound. In an embodiment where the organic semiconductor compound is a polyacene compound, a semiconductor crystal growth solution can include from about 0.5 wt-% to about 10 wt-% of the organic semiconductor compound. In an embodiment where the organic semiconductor compound is a polyacene compound, a semiconductor crystal growth solution can include, for example, from about 1 wt-% to about 8 wt-%, from about 1 wt-% to about 5 wt-%, or from about 1 wt-% to about 3 wt-% of the organic semiconductor compound. The amount of binder in the semiconductor crystal growth solution can be dictated, at least in part, by the solubility of the binder in the at least one solvent (in combination with other components of the semiconductor crystal growth solution). In an embodiment, the semiconductor crystal growth solution can include an amount of binder that is less than the solubility limit of the binder in the at least one solvent. In an embodiment, the semiconductor crystal growth solution can contain from about 0.05 wt-% to about 10.0 wt- % of binder. In an embodiment, the semiconductor crystal growth solution can contain from about 0.5 wt-% to about 2.0 wt-% of binder. In an embodiment, the semiconductor crystal growth solution can contain about 1.0 wt-% of binder.

Methods disclosed herein also include a step of forming an organic semiconductive layer upon evaporation of the at least one solvent from the semiconductor crystal growth solution. The semiconductive layer formed upon evaporation of at least a portion of the at least one solvent can be crystalline or partially crystalline (have both crystalline portions and amorphous portions). In an embodiment, the semiconductive layer formed upon evaporation of at least a portion of the at least one solvent can be crystalline or partially crystalline. In an embodiment, the semiconductive layer formed upon evaporation of at least a portion of the at least one solvent can be crystalline or more crystalline than amorphous. In an embodiment, the semiconductive layer formed upon evaporation of at least a portion of the at least one solvent can be crystalline or substantially crystalline.

The at least one solvent can evaporate entirely on its own in an uncontrolled fashion, or the conditions can be controlled in order to control the rate of evaporation. In an embodiment, the at least one solvent can be evaporated while slowing the evaporation rate by covering the coated semiconductor growth solution. In an embodiment, such conditions can lead to a semiconductive layer having a relatively high crystallinity. As discussed above, one embodiment of a method disclosed herein includes depositing at least one organic crystal of for example, an organic semiconductor compound on the surface before depositing a semiconductor crystal growth solution on the surface. Details surrounding such an embodiment were discussed above. In another embodiment, the at least one organic crystal can be deposited while the semiconductor crystal growth solution is being deposited. In such an embodiment, the semiconductor crystal growth solution generally includes the at least one organic crystal. Depositing a semiconductor crystal growth solution that includes the at least one organic crystal can be carried out in the same way that the semiconductor crystal growth solution without the at least one organic crystal can be deposited. The area of the surface on which a semiconductor crystal growth solution that includes at least one organic crystal can be deposited on can generally be the same as the area on which the semiconductor crystal growth solution (without the at least one organic crystal) can be deposited.

A semiconductor crystal growth solution that includes at least one organic crystal can be a saturated solution of the organic semiconductor material with at least one organic crystal contained therein. In embodiments where the at least one organic crystal is the same compound as the organic semiconductor material, the semiconductor crystal growth solution generally has at least one organic crystal and can have enough crystals to place them at a desired density across the desired area of the surface. In embodiments where the at least one organic crystal is not the same compound as the organic semiconductor material, the semiconductor crystal growth solution generally has at least one organic crystal and can have enough crystals to place them at a desired density across the desired area of the surface.

Semiconductor crystal growth solutions that include at least one organic crystal can be physically processed to control the size of the at least one organic crystal. The at least one organic crystal within the semiconductor crystal growth solutions can be processed in order to affect the size of the organic crystal. For example, if the organic crystal is to be made smaller, physical processing steps can be carried out to break the at least one organic crystal. Physical processing steps can include physically shaking the semiconductor crystal growth solutions, subjecting the semiconductor crystal growth solutions to ultrasound radiation, or filtering the semiconductor crystal growth solutions to remove crystals of a certain size.

Methods as disclosed herein can be utilized to prepare semiconductor devices that are generally fabricated by those of skill in the art. In an embodiment, methods as disclosed herein can be utilized to prepare semiconductor articles that include organic semiconductive layers. An exemplary semiconductive article would include a substrate upon which a semiconductive layer can be formed. A semiconductive layer formed as disclosed herein can be characterized by including at least one organic crystal which caused the nucleation of crystalline organic semiconductor material. Exemplary characterization methods include, but are not limited to optical microscopes. Such semiconductor articles including semiconductive layers can be a part of various semiconductor devices.

Also disclosed herein are semiconductive articles that include a substrate and a semiconductive layer disposed on the substrate, wherein the semiconductive layer comprises at least one organic crystal upon which organic semiconductor material nucleated and crystallized to form at least a portion of the semiconductive layer. The semiconductive layer can be disposed directly on the substrate or can be disposed on one or more layers or structures that are disposed on a substrate.

In an exemplary embodiment, an organic thin-film transistor (also referred to as a "TFT" _or "OTFT") can be prepared using methods as disclosed herein. An embodiment of an organic thin- film transistor 10 is shown in Figure IA. The OTFT 10 includes an optional substrate 12, a gate electrode 14 disposed on the optional substrate 12, a gate dielectric material 16 disposed on the gate electrode 14, an optional surface treatment layer 18 disposed on the gate dielectric layer 16, a source electrode 22, a drain electrode 24, and a semiconductive layer 20 that is in contact with both the source electrode 22 and the drain electrode 24. The source electrode 22 and the drain electrode 24 are separated from each other in an area on the surface of the semiconductive layer 20 (i.e., the source electrode 22 does not contact the drain electrode 24). The portion of the semiconductive layer 20 that is positioned between the source electrode 22 and the drain electrode 24 is referred to as the channel 21. The channel 21 is positioned over the gate electrode 14, the gate dielectric layer 16, and the optional surface treatment layer 18. The semiconductive layer 20 contacts the gate dielectric layer 16 or the surface treatment layer 18.

Another embodiment of an OTFT is shown in Figure IB. This OTFT 100 includes a gate electrode 14 disposed on an optional substrate 12, a gate dielectric layer 16 disposed on the gate electrode 14, an optional surface treatment layer 18 disposed on the gate dielectric layer 16, a semiconductive layer 20, and a source electrode 22 and a drain electrode 24 disposed on the semiconductive layer 20. In this embodiment, the semiconductive layer 20 is between the gate dielectric layer 16 and both the source electrode 22 and the drain electrode 24. The semiconductive layer 20 can contact the gate dielectric layer 16 or the optional surface treatment layer 18. The source electrode 22 and the drain electrode 24 are separated from each other (i.e., the source electrode 22 does not contact the drain electrode 24) in an area on the surface of the semiconductive layer 20.

The channel 21 is the portion of the semiconductive layer that is positioned between the source electrode 22 and the drain electrode 24. The channel 21 is positioned over the gate electrode 14, the gate dielectric layer 16, and the optional surface treatment layer 18.

In operation of the semiconductor device configurations shown in FIGS. IA and IB, voltage can be applied to the drain electrode 24. However, negligible charge (i.e., current) flows from the source electrode 22 unless voltage is also applied to the gate electrode 14. That is, unless voltage is applied to the gate electrode 14, the channel 21 in the semiconductive layer 20 remains in a non-conductive state. Upon application of voltage to the gate electrode 14, the channel 21 becomes conductive and charge flows through the channel 21 from the source electrode 22 to the drain electrode 24.

A substrate 12 often supports the OTFT during manufacturing, testing, and/or use. Optionally, the substrate can provide an electrical function for the OTFT. For example, the backside of the substrate can provide electrical contact. Useful substrate materials include, but are not limited to, inorganic glasses, ceramic materials, polymeric materials, filled polymeric materials (e.g., fiber-reinforced polymeric materials), metals, paper, woven or non- woven cloth, coated or uncoated metallic foils, or a combination thereof. Suitable polymeric substrates include acrylics, epoxies, polyamides, polycarbonates, polyimides, polyketones, polynorbornenes, polyphenyleneoxides, poly(ethylene naphthalate), poly(ethylene terephthalate), poly(phenylene sulfide), poly(ether ether ketones) such as poly(oxy-l,4-phenyleneoxy-l,4-phenylenecarbonyl-l,4-phenylene), and the like.

The gate electrode 14 can include one or more layers of a conductive material. For example, the gate electrode can include a doped silicon material, a metal, an alloy, a conductive polymer, or a combination thereof. Suitable metals and alloys include, but are not limited to, aluminum, chromium, gold, silver, nickel, palladium, platinum, tantalum, titanium, or a combination thereof. Exemplary conductive polymers include, but are not limited to, polyaniline or poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate). In some organic thin film transistors, the same material can provide both the gate electrode function and the support function of the substrate. For example, doped silicon can function as both the gate electrode and as a substrate.

The gate dielectric layer 16 is disposed on the gate electrode 14. This gate dielectric layer 16 electrically insulates the gate electrode 14 from the balance of the OTFT device. Useful materials for the gate dielectric include, for example, an inorganic dielectric material, a polymeric dielectric material, or a combination thereof. The gate dielectric can be a single layer or multiple layers of suitable materials. Each layer in a single or multilayer dielectric can include one or more dielectric materials.

Exemplary inorganic dielectric materials include strontiates, tantalates, titanates, zirconates, aluminum oxides, silicon oxides, tantalum oxides, titanium oxides, silicon nitrides, barium titanate, barium strontium titanate, barium zirconate titanate, zinc selenide, zinc sulfide, hafnium oxides, and the like. In addition, alloys, combinations, and multiple layers of these materials can be used for the gate dielectric layer 16.

Exemplary polymeric dielectric materials include polyimides, parylene C, crosslinked benzocyclobutene, cyanoethylpullulan, polyvinyl phenol, and the like. See, for example, C. D. Sheraw et al., "Spin-on polymer gate dielectric for high performance organic thin film transistors", Materials Research Society Symposium Proceedings, vol. 558, pages 403-408 (2000), Materials Research Society, Warrendale, Pa., USA; and U.S. Patent No. 5,347,144 (Gamier). Other exemplary organic polymeric dielectrics include cyano-functional polymers such as cyano-functional styrenic copolymers as disclosed in U.S. Patent No. 7,098,525 (Bai, et al.), the disclosure of which is incorporated herein by reference. Some of these polymeric materials can be coated from solution, can be crosslinked, can be photo- patterned, can have high thermal stability (e.g., stable up to a temperature of about 250° C), can have a low processing temperature (e.g., less than about 150° C or less than about 100° C), can be compatible with flexible substrates, or combinations thereof. Exemplary cyano-functional polymers that can be used as organic dielectric materials include, but are not limited to, styrene maleic anhydride copolymers modified by adding a methacrylate functional group for crosslinking purposes and by attaching cyano- functional groups; the reaction product of bis(2-cyanoethyl)acrylamide with an acrylated polystyrene macromer; polymers formed from 4-vinylbenzylcyanide; polymers formed from 4-(2,2'-dicyanopropyl)styrene; polymers formed from 4-( 1 , 1 ',2-tricyanoethyl)styrene; and polymers formed from 4-(bis-(cyanoethyl)aminoethyl)styrene; and a copolymer formed from 4-vinylbenzylcyanide and 4-vinylbenzylacrylate. Compounds disclosed in U.S. patent application publication US 2009/0001356-A1, the disclosure of which is incorporated herein by reference, can also be utilized as dielectric materials in devices disclosed herein.

The organic thin film transistors can include an optional surface treatment layer 18 disposed between the gate dielectric layer 16 and at least a portion of the organic semiconductive layer 20. One of skill in the art would know when optional surface treatment layers can be utilized and how to produce such surface treatment layers. Exemplary types of surface treatment layers can be found in U.S. Patent No. 6,433,359 (Kelley et al); and U.S. Patent No. 6,617,609 (Kelley et al.) for example. Other exemplary surface treatment layers can also include surface treatment layers formed from treatment of some inorganic oxide layers, such as silicon oxides, with silanes including hexamethyldisilazane and octadecyltrichlorosilane, for example. The source electrode 22 and drain electrode 24 can be metals, alloys, metallic compounds, conductive metal oxides, conductive ceramics, conductive dispersions, and conductive polymers, including, for example, gold, silver, nickel, chromium, barium, platinum, palladium, aluminum, calcium, titanium, indium tin oxide (ITO), fluorine tin oxide (FTO), antimony tin oxide (ATO), indium zinc oxide (IZO), poly(3,4- ethylenedioxythiophene) /poly(styrene sulfonate), polyaniline, other conducting polymers, alloys thereof, combinations thereof, and multiple layers thereof. Some of these materials are appropriate for use with n-type semiconductor materials and others are appropriate for use with p-type semiconductor materials, as is known in the art.

The thin film electrodes (e.g., the gate electrode, the source electrode, and the drain electrode) can be provided by any means known in the art such as physical vapor deposition (for example, thermal evaporation or sputtering), ink jet printing, or the like.

The patterning of these electrodes can be accomplished by known methods such as shadow masking, additive photolithography, subtractive photolithography, printing, microcontact printing, and pattern coating.

Methods of making thin film transistors are also disclosed herein. One such method, which can be used to form a bottom gate/bottom contact device generally produces the thin film transistors on a substrate and includes forming a gate electrode on the substrate; forming a dielectric layer on the gate electrode; forming a source electrode on the dielectric layer; forming a drain electrode on the dielectric layer, wherein the source electrode and the drain electrode are separated from each other at an area; and forming an organic semiconductive layer, wherein the organic semiconductive layer is positioned at least in a portion of the area separating the source electrode and the drain electrode, and wherein the organic semiconductive layer contacts both the source electrode and the drain electrode, by depositing at least one organic crystal in at least a vicinity of the source electrode and the drain electrode; depositing a semiconductor crystal growth solution in contact with the at least one organic crystal, wherein the semiconductor crystal growth solution includes at least one solvent and dissolved organic semiconductor compound; and forming an organic semiconductive layer upon evaporation of the at least one solvent from the semiconductor crystal growth solution.

Another exemplary method can be utilized to produce a bottom gate/top contact device generally produces the thin film transistors on a substrate and includes forming a gate electrode on the substrate; forming a dielectric layer on the gate electrode; and forming an organic semiconductive layer, wherein the organic semiconductive layer is positioned at least in a portion of the area that will separate the source electrode and the drain electrode, and wherein the organic semiconductive layer will contact both the source electrode and the drain electrode, by depositing at least one organic crystal in at least a vicinity of the source electrode and the drain electrode; depositing a semiconductor crystal growth solution in contact with the at least one organic crystal, wherein the semiconductor crystal growth solution includes at least one solvent and dissolved organic semiconductor compound; and forming an organic semiconductive layer upon evaporation of the at least one solvent from the semiconductor crystal growth solution; forming a source electrode on the semiconductive layer; and forming a drain electrode on the semiconductive layer, wherein the source electrode and the drain electrode are separated from each other at an area.

Another exemplary method can be utilized to produce a top gate/bottom contact device generally produces the thin film transistors on a substrate and includes forming a source electrode on the substrate; and forming a drain electrode on the substrate, wherein the source electrode and the drain electrode are separated from each other in an area; forming an organic semiconductive layer, wherein the organic semiconductive layer is positioned at least in a portion of the area separating the source electrode and the drain electrode, and wherein the organic semiconductive layer contacts both the source electrode and the drain electrode, by depositing at least one organic crystal in at least a vicinity of the source electrode and the drain electrode; depositing a semiconductor crystal growth solution in contact with the at least one organic crystal, wherein the semiconductor crystal growth solution includes at least one solvent and dissolved organic semiconductor compound; and forming an organic semiconductive layer upon evaporation of the at least one solvent from the semiconductor crystal growth solution; forming a dielectric layer on the semiconductive layer; and forming a gate electrode on the substrate.

Another exemplary method can be utilized to produce a top gate/top contact device generally produces the thin film transistors on a substrate and includes forming an organic semiconductive layer on the substrate by depositing at least one organic crystal on a portion of the substrate; depositing a semiconductor crystal growth solution in contact with the at least one organic crystal, wherein the semiconductor crystal growth solution includes at least one solvent and dissolved organic semiconductor compound; and forming an organic semiconductive layer upon evaporation of the at least one solvent from the semiconductor crystal growth solution; forming a source electrode on the semiconductive layer; forming a drain electrode on the semiconductive layer, wherein the source electrode and the drain electrode are separated from each other in an area; forming a dielectric layer on the source electrode, the drain electrode, and the organic semiconductive layer; and forming a gate electrode on the dielectric layer. EXAMPLES

Mobility Value Test Method:

The saturation field effect mobility (μ) was determined in air using two Source Measure Units (Model 2400 from Keithley Instruments, Inc. (Cleveland, OH)). The devices were placed on an S-1160 Series probe station and probes connected using S-725- PRM manipulators (both available from Signatone Corp., Gilroy, CA). The drain to source bias voltage (V_DS) was held at -60 V, while the gate to source bias (V_GS) was incremented over the range +10 V to -60 V in 1 V steps. The drain-source current (I_DS) was measured as a function of gate-source voltage bias (V_GS) from +10V to -60V at a constant drain- source voltage bias (V_DS) of -60V. The saturation field effect mobility (μ) was calculated from the slope of the linear portion of the plot of the square root of I_DS versus V_GS using the equation

ID_S = μWC(V_GS-V,)² ÷ 2L where C is the specific capacitance of the gate dielectric, W is the channel width, and L is the channel length.

Using a plot of the square root of I_DS versus V_GS curve, the X-axis extrapolation of a straight-line fit was taken as the threshold voltage (Vt). In addition, plotting I_DS (using a log-scale) as a function of V_GS afforded a curve where a straight line fit was drawn along a portion of the curve containing V_t. The inverse of the slope of this line was the subthreshold slope (S). The on/off ratio was taken as the difference between the minimum and maximum drain current (ID_S) values of the ID_S - V_GS curve.

Example 1 TIPS was used as both the organic crystal and as the organic semiconductor compound. TIPS can be prepared as described in U.S. Patent No. 6,690,029 Bl or in PCT patent publication WO 2005/055248. TIPS in the solid, crystalline form was placed in a glass vial, and then enough toluene was added to provide 7.5 wt-% TIPS in toluene. The vial was capped, covered with aluminum foil to shield it from light, and placed on a shaker for 1 day. Afterwards, a pipette drop of the mixture in the vial was placed on a glass slide, and immediately another glass slide was placed over the solution, and the mixture was immediately viewed under an optical microscope (Olympus MX50). No crystals of TIPS could be observed.

A small amount (spatula tip) of TIPS crystals was placed on another glass slide, and the slide lightly shaken to disperse the crystals on the surface of the slide. Then a pipette drop of the mixture (made above) was placed on the glass slide at the area with the TIPS crystals. A glass slide was immediately placed over the solution, and the sample was immediately viewed under the optical microscope. A TIPS crystal on the glass slide and in the saturated TIPS solution was quickly found and was monitored over time. Optical micrographs were taken periodically over the span of approximately 15 minutes with the optical microscope in Differential Interference Contrast (DIC) mode. The optical micrographs, in chronological order are presented in Figures 2A through 2F. The optical micrographs show the nucleation and growth of TIPS from the TIPS crystal that was placed on the slide prior to the placement of the drop of solution.

Example 2

TIPS in the solid, crystalline form was placed in a glass vial, and then enough cyclohexane was added to provide 1 wt-% TIPS in cyclohexane. The vial was capped, and sonicated for approximately 100 minutes in the dark. Afterwards, a pipette drop of the solution in the vial was placed on a heavily n-doped silicon wafer with 1000 Angstroms of thermal oxide as dielectric which had been surface-treated with hexamethyldisilazane (HMDS). Surface treatment was done by spin coating the wafer with hexamethyldisilazane. The wafer was stored in a wafer carrier for at least 8 hours before use. The solution of 1 wt.% TIPS in cyclohexane was placed on the surface-treated thermal oxide, and the cyclohexane allowed to evaporate. An optical micrograph of the TIPS deposits on the surface is shown in Figure 3.

In this example, once the TIPS crystals have been deposited as exemplified above, a semiconductor crystal growth solution can be coated onto the surface to form a semiconductive layer.

Example 3

Synthesis of 6.13-Bis(3.3.4.4.5.5.6.6.7.7.8.8.9.9.10.10.10- heptadecafluorodecyldiisopropylsilylethvnvDpentacene The intermediate compound (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- heptadecafluorodecyldiisopropylsilyl)acetylene was prepared using the following procedure. In an oven-dried 250-mL round bottom flask,

S^^^^^^^JJ^^^^JOJOJO-heptadecafiuorodecyltrichlorosilane (8.7 grams, 15 mmol) (Gelest, Inc., Morris ville, PA) was dissolved in anhydrous tetrahydrofuran (THF) (10 mL). In a separate oven-dried 100-mL round bottom flask, (trimethylsilyl)acetylene (1.7 g, 18 mmol) (GFS Chemical, Columbus, OH) was dissolved in anhydrous THF (15 mL) and cooled in an ice bath, followed by the dropwise addition of n-butyllithium (6.0 mL, 15 mmol, 2.5 M in hexanes) (Sigma- Aldrich, Milwaukee, WI). This second solution was stirred for 1 hour, then added to the first solution dropwise over a period of 45 minutes. The resulting solution was stirred for 5 hours, then cooled in an ice bath. Isopropyllithium (43 mL, 30 mmol, 0.7 M in pentane) (Sigma- Aldrich, Milwaukee, WI) was added slowly, then stirring was continued for 12 hour. The reaction mixture was poured into 100 mL of a dilute ammonium chloride solution, then rinsed in with hexanes (40 mL). The organic layer was separated, and the aqueous layer was extracted a second time (30 mL hexanes). The organic layers were combined, washed with water (3 x 20 mL), dried over magnesium sulfate, filtered, and concentrated under vacuum to yield the crude product mixture. The product was isolated using chromatography on silica gel with hexanes as eluant and was concentrated to yield a colorless liquid (3.9 grams, 6.0 mmol). To remove the trimethylsilyl-endcap, the product was taken up in THF (about 15 mL) and methanol (about 5 mL) and purged vigorously for 15 minutes. Purging was continued after the addition of 4 drops of a 15 wt-% aqueous sodium hydroxide solution. The reaction was allowed to stir with continued (but less vigorous) purging for 45 minutes. The mixture was extracted into hexanes with the addition of water, washed with 10 wt-% hydrochloric acid solution (<5 mL) and water (3 x 20 mL), dried over magnesium sulfate, filtered, and concentrated under vacuum, to yield the product (3.4 grams, 5.9 mmol, yield 39 wt-%) as a colorless liquid. ¹H-NMR (200 MHz, CDCl₃) δ = 2.4 (s, IH), 2.2 (m, 2H), 1.0 (m, 14H), 0.8 (m, 2H).

The compound 6,13-bis(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- heptadecafluorodecyldiisopropylsilylethyny^pentacene was synthesized using the following procedure. In an oven-dried 100-mL round bottom flask, 1.8 grams (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafiuorodecyldiisopropylsilyl)acetylene (3.1 mmol) was dissolved in anhydrous THF (5 rnL). Isopropylmagnesium chloride (1.3 rnL, 2.5 mmol, 2 M in THF) (Sigma- Aldrich, Milwaukee, WI) was added and the mixture was heated to 60 ⁰C for 2 hours. After removing the reaction mixture from the heat, pentacene quinone (0.34 g, 1.1 mmol) (Sigma- Aldrich, Milwaukee, WI) was added and the flask was returned to heating at 60 ⁰C, which was continued for 12 hours. The reaction was quenched by the addition of 3 drops of a saturated ammonium chloride solution. Separately, a stannous chloride solution was made by dissolving stannous chloride dihydrate (0.90 grams, 4.0 mmol) in 1.5 mL 10 wt-% aqueous hydrochloric acid, then this solution was added to the quenched reaction mixture. Stirring was continued for 10 minutes, then 50 mL methanol was added to precipitate the product, aided by refrigeration for 1 hour. The solid was collected by filtration, then taken up in hexanes and rinsed onto a thick plug of silica gel. Hexanes was flushed through the plug to elute excess acetylene, then the product was eluted using 8:1 hexanes :dichloromethane. Solvent was removed to yield 0.25 grams (0.17 mmol) as a blue solid, which recrystallized from about 15 mL acetone to yield 0.13 grams (0.9 mmol, 8 wt-% from quinone) crystalline blue plates. ¹H-

NMR (200 MHz, CDCl₃) δ = 9.2 (s, 4H), 8.0 (dd, J= 3.4 Hz, 6.6 Hz), 7.4 (dd, J= 3.2 Hz, 7.0 Hz), 2.5 (m, 4H), 1.4 (m, 28H). 1.2 (m, 4H).

Preparation of a Semiconductor Crystal Growth Solution 6,13-Bis(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- heptadecafluorodecyldiisopropylsilylethyny^pentacene (0.0106 grams) was added to a glass vial, and then l,3-bis(trifluoromethyl)benzene (0.5836 grams) (Sigma- Aldrich, Milwaukee, WI) was added to the vial. The vial was capped, and then wrapped with aluminum foil to shield the composition from light. The vial stood for a couple of hours and then was placed on a IKA LABORTECHNIK HS501 shaker (IKA Werke GmbH &

Co. KG, Staufen, Germany) and shaken for approximately 48 hours. The contents of the vial were filtered through a polytetrafluoroethylene (PTFE) filter with a pore size of 0.2 micron and 25 mm diameter that is commercially available under the trade designation ACRODISC CR from Pall Life Sciences (East Hills, NY). Formation of an Organic Semiconductive Layer of a Thin Film Transistor A piece of n-type silicon wafer with thermal oxide (a 4 inch diameter silicon <100> wafer, which was highly doped n+ (arsenic) with a resistivity of <0.005 ohm-cm and supplied with a 1000 Angstrom thermal oxide (SiO₂) on the front surface and coated with 100 Angstrom TiN and 5000 Angstrom aluminum on the back surface from Noel

Technologies, Inc. , Campbell, CA, was cleaved approximately into sixths to yield the piece) was treated for 4 minutes in a Plasma Cleaning System (Model YES-GlOOO from Yield Engineering Systems, Inc., Livermore, California) using a power setting of 500 Watts and oxygen pressure of approximately 200 milli-Torr. A very small amount (spatula tip) of 6,13-Bis(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- heptadecafluorodecyldiisopropylsilylethyny^pentacene crystals was placed on the thermal oxide surface of the silicon wafer. Then the semiconductor crystal growth solution of 6,13-bis(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- heptadecafluorodecyldiisopropylsilylethyny^pentacene in 1 ,3-bis(trifluoromethyl)benzene (Sigma- Aldrich, Milwaukee, WI) was knife coated onto the wafer. The knife coater blade was placed approximately 0.005 inches above the thermal oxide surface, and a disposable glass pipette was used to place a small bead of the semiconductor crystal growth solution between the blade and the thermal oxide surface. The knife coater was then drawn by hand over the wafer to coat the wafer with the semiconductor crystal growth solution. Immediately after knife coating the semiconductor crystal growth solution, the solution- coated wafer was covered with a glass petri dish (approximately 90 mm diameter x 15 mm deep) to slow the solvent, l,3-bis(trifluoromethyl)benzene, evaporation. The sample was left to dry at room temperature in extremely dim room light. After approximately 2 to 3 hours, the sample was dry. Gold source and drain electrodes (approximately 600 Angstroms thick) were vapor deposited through a shadow mask onto the semiconductor layer using a thermal evaporator, thus forming transistors with a bottom gate, top contact architecture. Source and drain electrodes were oriented with the long dimension of the electrodes, the channel width, perpendicular to the knife coating direction. The channel length was approximately 100 micrometers and the channel width was approximately 1000 micrometers. Three thin film transistors that were very near the crystals of 6,13- bis(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- heptadecafluorodecyldiisopropylsilylethyny^pentacene that were deposited onto the thermal oxide surface prior to knife coating of the semiconductor crystal growth solution were tested for electrical performance as described in the Mobility Value Test Method. These three thin film transistors exhibited transistor behavior, that is, they functioned. The mobilities of the transistors were 8.15 x 10^~5, 4.50 x 10^~5, and 3.20 x 10^"5 cm²/V-s.

Comparative Example 1

A solution of 6,13-Bis(3,3 ,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- heptadecafluorodecyldiisopropylsilylethyny^pentacene in 1 ,3-bis(trifluoromethyl)benzene was prepared as described above in Example 3, Preparation of a Semiconductor Crystal Growth Solution. The solution was knife-coated onto a piece of n-type silicon wafer with thermal oxide and thin film transistors prepared in the same manner as described above in Example 3, Formation of an Organic Semiconductive Layer of a Thin Film Transistor, except no crystals of 6,13-Bis(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- heptadecafluorodecyldiisopropylsilylethyny^pentacene were placed on the thermal oxide surface prior to knife-coating of the solution. The semiconductive layers of the transistors had relatively weak crystalline textures relative to the those of the three transistors described in Example 3 as observed by optical microscopy. The transistors did not exhibit transistor behavior as measured by the Mobility Value Test Method.

Thus, embodiments of methods of fabricating organic semiconductive layers are disclosed. One skilled in the art will appreciate that the present disclosure can be practiced with embodiments other than those disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation, and the present disclosure is limited only by the claims that follow.

Claims

What is claimed is:

1. A method of preparing a semiconductor device comprising: depositing at least one organic crystal on a surface; depositing a semiconductor crystal growth solution in contact with the at least one organic crystal, wherein the semiconductor crystal growth solution comprises at least one solvent and dissolved organic semiconductor compound; and forming an organic semiconductive layer upon evaporation of the at least one solvent from the semiconductor crystal growth solution.

2. The method according to claim 1, wherein the organic crystal is an organic semiconductor crystal.

3. The method according to claim 1 or 2, wherein the dissolved organic semiconductor compound and the at least one organic crystal are the same compound.

4. The method according to any one of claims 1 to 3, wherein the dissolved organic semiconductor compound, the at least one organic crystal, or both are a polyacene based compound.

5. The method according to any one of claims 1 to 4, wherein the dissolved organic semiconductor compound, the at least one organic crystal, or both are compounds of Formula III:

Ol Ix_xIx ..Ix _z

Formula III wherein: each R, R' and R" independently comprises (i) hydrogen, (ii) a branched or unbranched, substituted or unsubstituted alkyl group, (iii) a branched or unbranched, substituted or unsubstituted alkenyl group, (iv) a substituted or unsubstituted cycloalkyl group, (v) a substituted or unsubstituted cycloalkylalkylene group, (vi) a branched or unbranched, substituted or unsubstituted alkynyl group, (vii) a substituted or unsubstituted aryl group, (viii) a substituted or unsubstituted arylalkylene group, (ix) an acetyl group, (x) a substituted or unsubstituted heterocyclic ring comprising at least one of O, N, S and Se in the ring, (xi) a substituted or unsubstituted ether group or polyether group, or (xii) a substituted or unsubstituted sulfonamide group; at least one R, R' or R" comprises a fluorinated monovalent radical comprising one or more fluorine atoms with said one or more fluorine atoms being separated from either silicon atom by at least three atoms or four covalent bonds; x, y and z each independently equal 0, 1, 2 or 3; (x + y + z) = 3; and each X independently comprises (i) hydrogen, (ii) a halogen, (iii) a branched or unbranched, substituted or unsubstituted alkyl group, (iv) a substituted or unsubstituted aryl group, (v) a branched or unbranched, substituted or unsubstituted alkenyl group, (vi) a branched or unbranched, substituted or unsubstituted alkynyl group, (vii) a cyano group, (viii) a nitro group, (ix) a branched or unbranched, substituted or unsubstituted alkoxy group, or (x) any two adjacent X groups combine to form (a) a substituted or unsubstituted carbocyclic ring or (b) a substituted or unsubstituted heterocyclic ring.

6. The method according to any one of claims 1 to 4, wherein the dissolved organic semiconductor compound, the at least one organic crystal, or both are compounds of

Formula III

Formula III wherein: each R independently comprises (i) a branched or unbranched, substituted or unsubstituted alkyl group, (ii) a substituted or unsubstituted cycloalkyl group, or (iii) a substituted or unsubstituted cycloalkylalkylene group; each R' independently comprises (i) a branched or unbranched, substituted or unsubstituted alkenyl group, (ii) a substituted or unsubstituted cycloalkyl group, or (iii) a substituted or unsubstituted cycloalkylalkylene group; R" comprises (i) hydrogen, (ii) a branched or unbranched, substituted or unsubstituted alkynyl group, (iii) a substituted or unsubstituted cycloalkyl group, (iv) a substituted or unsubstituted cycloalkylalkylene group, (v) a substituted aryl group, (vi) a substituted or unsubstituted arylalkylene group, (vii) an acetyl group, or (viii) a substituted or unsubstituted heterocyclic ring comprising at least one of O, N, S and Se in the ring; x = l or 2; y = 1 or 2; z = 0 or 1 ; (x + y + z) = 3; and each X independently comprises (i) hydrogen, (ii) a halogen, (iii) a branched or unbranched, substituted or unsubstituted alkyl group, (iv) a substituted or unsubstituted aryl group, (v) a branched or unbranched, substituted or unsubstituted alkenyl group, (vi) a branched or unbranched, substituted or unsubstituted alkynyl group, (vii) a substituted or unsubstituted heterocyclic group, (viii) a cyano group, (iv) an ether group, (x) a branched or unbranched, substituted or unsubstituted alkoxy group, (xi) a nitro group, or (xii) any two adjacent X groups form (a) a substituted or unsubstituted carbocyclic ring or (b) a substituted or unsubstituted heterocyclic ring.

7. The method according to any one of claims 1 to 4, wherein the dissolved organic semiconductor compound, the at least one organic crystal, or both are compounds of formula II

Formula II

wherein each of Ri, R₂, R3, R₄, Rs, R9, Rio, Rn, R15, Ri6, and Rn each independently is hydrogen; a substituted or unsubstituted C1-C40 alkyl or alkenyl group that can be cyclic, linear, branched or a combination thereof; a substituted or unsubstituted C1-C40 alkoxy group; a substituted or unsubstituted C₆-C₄O aryloxy group; a substituted or unsubstituted Ci-C₄₀ carbonyl group; a substituted or unsubstituted C₂-C₄₀ alkoxycarbonyl group; a substituted or unsubstituted Cy-C₄₀ aryloxycarbonyl group; a substituted or unsubstituted C₂-C₄₀ alkylcarbonyloxy group; a substituted or unsubstituted Cy-C₄₀ arylcarbonyloxy group; a substituted or unsubstituted amino carbonyl group (-C(=O)NR_aRb wherein R₃ and R_b are independently a hydrogen or a substituted or unsubstituted hydrocarbyl group); a halogen; a cyano group; a nitro group; a substituted or unsubstituted heterocyclic ring comprising at least one of O, N, S, and Se in the ring; a substituted or unsubstituted silyl group; or a substituted or unsubstituted silylalkynyl group; and wherein independently each pair of R₂ and R₃ and/or R₉ and Ri₀, may be cross-bridged to form a C₄-C₄₀ saturated or unsaturated ring, which saturated or unsaturated ring may be intervened by O, S, Se, or N(Ra) where Ra is defined as above; and wherein A represents silicon or germanium.

8. The method according to any one of claims 1 to 4, wherein the dissolved organic semiconductor compound, the at least one organic crystal, or both are compounds of formula III

Formula IV

wherein each of R₂, R3, R7, Rs, R15, Ri6, and Rn each independently is hydrogen; a substituted or unsubstituted C1-C40 alkyl or alkenyl group that can be cyclic, linear, branched or a combination thereof; a substituted or unsubstituted C₁-C₄₀ alkoxy group; a substituted or unsubstituted C₆-C₄O aryloxy group; a substituted or unsubstituted C1-C40 carbonyl group; a substituted or unsubstituted C2-C40 alkoxycarbonyl group; a substituted or unsubstituted C7-C40 aryloxycarbonyl group; a substituted or unsubstituted C2-C40 alkylcarbonyloxy group; a substituted or unsubstituted C₇-C₄₀ arylcarbonyloxy group; a substituted or unsubstituted amino carbonyl group (-C(=O)NRaRb wherein R₃ and Rb are independently a hydrogen or a substituted or unsubstituted hydrocarbyl group); a halogen; a cyano group; a nitro group; a substituted or unsubstituted heterocyclic ring comprising at least one of O, N, S, and Se in the ring; a substituted or unsubstituted silyl group; or a substituted or unsubstituted silylalkynyl group; and wherein independently each pair of R₂ and R3 and/or R₇ and Rg, may be cross-bridged to form a C4-C40 saturated or unsaturated ring, which saturated or unsaturated ring may be intervened by O, S, Se, or N(R_a) where R_a is defined as above; and wherein A represents silicon or germanium.

9. The method according to any one of claims 1 to 4, wherein the dissolved organic semiconductor compound, the at least one organic crystal, or both are 6,13- bis(triisopropylsilyl-ethynyl)pentacene, 6, 13-bis(allyldiisopropylsilylethynyl)pentacene, 6,13-bis(iso-propenyldiisopropylsilylethynyl)pentacene, 6,13- bis(cyclopropyldiisopropylsilylethynyl) pentacene, 6,13-bis(l- methylenepropyldiisopropylsilylethynyl)pentacene, 6,13- bis(diisopropenylisopropylsilylethynyl)pentacene, and 6,13- bis(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- heptadecafluorodecyldiisopropylsilylethyny^pentacene.

10. The method according to any one of claims 1 to 9, wherein the semiconductor crystal growth solution further comprises at least one binder.

11. The method according to claim 10, wherein the at least one binder is polystyrene, poly(α-methyl styrene), poly(4-methylstyrene), poly(pentafluorostyrene), or copolymers of styrene.

12. The method according to any one of claims 1 to 11, wherein the at least one organic crystal is present in the semiconductor crystal growth solution before the semiconductor crystal growth solution is deposited on the surface.

13. The method according to claim 12, wherein semiconductor crystal growth solution is saturated with respect to the dissolved organic semiconductor compound.

14. The method according to any one of claims 1 to 11, wherein the at least one organic crystal is deposited on the surface before the semiconductor crystal growth solution is deposited.

15. The method according to claim 14, wherein the at least one organic crystal and the dissolved organic semiconductor compound are the same compound.

16. The method according to claim 14 or 15, wherein the at least one organic crystal is deposited on the surface by coating the surface with a nucleating solution of the organic semiconductor material.

17. The method according to claim 16, wherein the nucleating solution of the organic semiconductor material has a lower concentration of organic semiconductor than that of the semiconductor crystal growth solution.

18. A method of making a thin film transistor on a substrate, the method comprising: forming a gate electrode on a substrate; forming a dielectric layer on the gate electrode; forming a source electrode on the dielectric layer; forming a drain electrode on the dielectric layer, wherein the source electrode and the drain electrode are separated from each other at an area; and forming an organic semiconductive layer, wherein the organic semiconductive layer is positioned at least in a portion of the area separating the source electrode and the drain electrode, and wherein the organic semiconductive layer contacts both the source electrode and the drain electrode, by depositing at least one organic crystal at least in the vicinity of the source electrode and the drain electrode; depositing a semiconductor crystal growth solution in contact with the at least one organic crystal, wherein the semiconductor crystal growth solution comprises at least one solvent and dissolved organic semiconductor compound; and forming an organic semiconductive layer upon evaporation of the at least one solvent from the semiconductor crystal growth solution.

19. The method according to claim 18, wherein the at least one organic crystal is present in the semiconductor crystal growth solution before the semiconductor crystal growth solution is deposited.

20. The method according to claim 18, wherein the at least one organic crystal is deposited before the semiconductor crystal growth solution is deposited.