JP2012066982A - Method for producing compound semiconductor particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily produce a chalcopyrite type compound by low temperature heating without making the process complicated.SOLUTION: A first solution is prepared by dissolving two or more cation raw materials comprising metal salts such as CuI and InIin oleylamine. A second solution is prepared by dissolving an alkylsilylated sulfur compound such as bistrimethylsilyl sulfide in octadecene. A mixed solution is prepared by mixing the first solution and the second solution. The mixed solution is heat treated at a low temperature of 160°C to produce nanoparticles of a compound semiconductor having a chalcopyrite structure, such as CuInS.

Description

  The present invention relates to a method for producing compound semiconductor particles, and more particularly to a method for producing a compound semiconductor having a chalcopyrite structure.

  Chalcopyrite type compounds, which are a type of compound semiconductor, are attracting attention as materials for optoelectronic devices.

The chalcopyrite compounds has a tetragonal crystal structure as overlapped two stages sphalerite structure cubic in the c-axis direction, I-III-VI ₂ group, II-III ₂ -VI _{4 group, I 2 -II-IV-VI} 4 group compound or the like, the presence of various compounds are known.

  Since this chalcopyrite type compound is a direct transition semiconductor, it is expected to be a new solar cell material to replace Si because it has excellent light absorption characteristics, hardly causes photodegradation, and has excellent radiation resistance. Furthermore, the chalcopyrite type compound can cover a wide band gap and can cover a wide range of wavelengths, and thus can be used as a light emitting / receiving element from the infrared region to the ultraviolet region.

  On the other hand, nanoparticles with a particle size of 10 nm or less can be controlled in a wide wavelength range using the quantum size effect, and thus are attracting attention for application to photoelectric conversion devices such as solar cells and light-emitting diodes (LEDs). ing.

  Therefore, in recent years, a technique for producing nanoparticles of a chalcopyrite type compound has been actively studied.

For example, Patent Document 1, a first compound comprising a I-III-VI ₂ group elements each one element having a chalcopyrite structure, particles consisting of the first compound, an outer diameter 0. A phosphor having a fluorescence quantum yield of emitting light waves excited by excitation light at 5 to 20.0 nm is 3.0% or more and 20.0% or less at room temperature.

  In Patent Document 1, a first solution in which raw material salts of a plurality of types of elements constituting a compound of a chalcopyrite structure are dissolved and mixed in a solution to which a complexing agent of the plurality of types of elements is added, and chalcogenite The second solution in which is dissolved is mixed, pretreated under predetermined pretreatment conditions, and then heat treated under predetermined heating conditions to produce a phosphor.

Specifically, in Patent Document 1, copper iodide (I) and indium iodide (III) are dissolved in oleylamine to prepare a first solution, and thioacetamide is dissolved in trioctylphosphine to form a second solution. Is making. Then, a reaction solution obtained by mixing the first solution and the second solution is aged for 24 hours at a temperature of 25 ° C. in an argon atmosphere, and then the reaction solution is heated at a temperature of 160 ° C. to 280 ° C. for 3 seconds to 10 seconds. The phosphor is made of CuInS ₂ by reacting by heating for a minute.

  In Patent Document 1, as a chalcogenide compound containing chalcogen, hydrogen sulfide, thiourea, trioctylphosphine sulfide, etc. can be used in addition to thioacetamide, and sulfur is directly reacted with a metal salt. Thus, it is possible to obtain a chalcopyrite type compound.

  Patent Document 2 discloses the production of chalcopyrite nanoparticles in which a periodic table group Ib metal compound, group IIIb metal compound, and group VIb compound are mixed in an organic solvent to form nanoparticles. A method has been proposed.

  This Patent Document 2 describes a method for producing chalcopyrite nanoparticles through a two-step process and a method for producing them in one step.

  In the case of manufacturing through the two-step process, first, copper sulfate and oleylamine are mixed in dioctyl ether, stirred for several minutes in an argon atmosphere, then heated to 100 ° C., and sulfur is dissolved in dodecanethiol. The solution is added and stirred and then centrifuged to obtain copper sulfide nanoparticles (first stage).

Next, indium acetate and 1-dodecanethiol were mixed in trioctylamine, heated to 90 ° C. with stirring under an argon atmosphere, and a solution in which copper sulfide nanoparticles were dissolved in trioctylamine was added. The mixture was stirred at a temperature of 30 ° C. for 30 minutes, thereby obtaining chalcopyrite nanoparticles CuInS ₂ (second stage).

On the other hand, when producing in said 1 process, after mixing copper acetate and indium acetate, and 1-dodecanethiol in trioctylamine, heating up to 90 degreeC, stirring in argon atmosphere, The mixture was heated to 200 ° C. and stirred for 30 to 120 minutes, whereby CuInS ₂ as chalcopyrite nanoparticles was obtained.

JP 2007-169605 A (Claims 1, 2, 26, paragraph numbers [0051], [0052]) JP 2008-192542 A (Claim 1, paragraph numbers [0050] and [0052])

  However, the manufacturing methods of Patent Documents 1 and 2 have the following problems.

  That is, in Patent Document 1, in the process of producing nanoparticles, the second solution, which is a precursor solution, must be aged for a long time (for example, 24 hours) at room temperature, and thus a final product is obtained. There was a problem that it took a long time to inferior productivity. That is, since a low-reactivity thioacetamide is used as the chalcogenide compound, it takes a long time for ripening, and therefore there is a problem that productivity is inferior.

  Further, when hydrogen sulfide or thiourea is used as the chalcogenide compound, these are highly toxic, so environmental considerations must be taken into account, and expensive peripheral equipment is required.

  Further, when trioctylphosphine sulfide is used as the chalcogenide compound, the reactivity is low as well as thioacetamide, and the material cost is high.

  Further, when sulfur alone as a chalcogen is used, it is necessary to react at a high temperature, requiring high energy, resulting in inferior production efficiency and expensive manufacturing equipment.

  On the other hand, in Patent Document 2, in the case of producing in a two-step process, since the CuS nanoparticles are produced and then In is doped, the process becomes complicated. Moreover, when producing by 1 process, it must heat at 200 degreeC high temperature for a long time (for example, 30 to 120 minutes), requires high energy, is inferior in production efficiency, and also manufacture equipment becomes expensive.

  This invention is made in view of such a situation, Comprising: It aims at providing the manufacturing method of the compound semiconductor which can manufacture a chalcopyrite type compound easily by low-temperature heating, without complicating a process. To do.

  The present inventor conducted intensive research to achieve the above object, and by using an alkylsilylated sulfur compound for a chalcogenide-containing chalcogenide compound, it is easy to form a cation raw material comprising a metal salt with low-temperature heating. The present inventors have found that a chalcopyrite type compound can be produced efficiently with low energy.

  The present invention has been made on the basis of such knowledge, and the method for producing compound semiconductor particles according to the present invention comprises reacting two or more kinds of cation raw materials comprising a metal salt with an alkylsilylated sulfur compound in a liquid phase. And producing compound semiconductor particles having a chalcopyrite structure.

  In the method for producing compound semiconductor particles of the present invention, the reaction in the liquid phase is preferably performed under low temperature heating of 160 ° C. or lower.

  In the method for producing compound semiconductor particles of the present invention, the cation raw material is dissolved in a first organic solvent to prepare a first solution, and the alkylsilylated sulfur compound is dissolved in a second organic solvent. It is also preferable to prepare a second solution, mix the first solution and the second solution to prepare a mixed solution, and heat the mixed solution at a predetermined low temperature.

  In the method for producing compound semiconductor particles of the present invention, the cation raw material is dissolved in a first organic solvent to prepare a first solution, and the alkylsilylated sulfur compound is dissolved in a second organic solvent. It is also preferable to prepare a second solution, heat-treat the first solution at a predetermined low temperature, and add the second solution to the heated first solution.

  In the method for producing compound semiconductor particles of the present invention, the predetermined low temperature is preferably 160 ° C. or lower.

The production method of a compound semiconductor particles of the present invention, the chalcopyrite structure, I-III-VI ₂ group of the Periodic Table, II-III ₂ -VI _{4 group, I 2 -II-IV-VI} 4 group Preferably, the element belonging to Group VI and the element belonging to Group VI is sulfur.

  In the method for producing compound semiconductor particles of the present invention, the alkylsilylated sulfur compound preferably contains bistrimethylsilyl sulfide and bistrylethylsilyl sulfide.

According to the manufacturing method of the compound semiconductor particles, and alkylsilyl sulfur compounds such as cationic material and bis-trimethylsilyl sulfide and bis tolyl triethylsilyl sulfide comprising a metal salt are reacted in the liquid phase, I-III-VI ₂ group, Since compound semiconductor particles having a chalcopyrite structure such as II-III ₂ -VI ₄ group, I ₂ -II-IV-VI ₄ group and the like can be produced, the cation raw material and the chalcogenite compound can be synthesized at a low temperature, A chalcopyrite compound can be easily produced at low cost without complicating the process.

  In addition, by performing the reaction in the liquid phase under low-temperature heating at 160 ° C. or lower, the energy cost can be suppressed, and a chalcopyrite compound can be obtained without requiring special equipment.

  The cation raw material is dissolved in a first organic solvent to prepare a first solution, and the alkylsilylated sulfur compound is dissolved in a second organic solvent to prepare a second solution, The first solution and the second solution are mixed to prepare a mixed solution, and the mixed solution is heated at a predetermined low temperature (for example, 160 ° C. or lower). An organic solvent having a relatively low boiling point can also be used, and the degree of freedom in selecting an organic solvent can be expanded.

  The cation raw material is dissolved in a first organic solvent to prepare a first solution, and the alkylsilylated sulfur compound is dissolved in a second organic solvent to prepare a second solution. When the solution is heat-treated at a predetermined low temperature (for example, 160 ° C. or lower) and the second solution is added to the heated first solution, an organic solvent having a relatively low boiling point is used as described above. This is possible, and the degree of freedom in selecting an organic solvent can be expanded.

It is a figure which shows the X-ray-diffraction spectrum of an Example sample. It is a figure which shows the X-ray-diffraction spectrum of a comparative example sample.

  Next, the form for implementing this invention is explained in full detail.

  In the method for producing compound semiconductor particles according to the present invention, compound semiconductor particles having a chalcopyrite structure are produced by reacting two or more kinds of cation raw materials composed of metal salts with an alkylsilylated sulfur compound in a liquid phase.

  A compound semiconductor having a chalcopyrite structure is generally composed of a cation raw material composed of a metal salt containing a metal element belonging to groups Ib to IVb of the periodic table, and a chalcogenide compound containing chalcogen which is a group VIb element or a single chalcogen. It can be produced by reaction.

  Therefore, in this type of compound semiconductor, when the chalcogen is composed of a sulfur element, a sulfur compound that reacts in the presence of a metal ion can be used as the chalcogenide compound.

  However, as described in [Background Art] and [Problems to be Solved by the Invention], when thioacetamide or trioctylphosphine sulfide is used as a sulfur compound, these are both low in reactivity and heated. The precursor solution must be aged for a long time before processing.

  On the other hand, when hydrogen sulfide or thiourea is used, environmental considerations are necessary due to its toxicity, and thus expensive equipment is required. In addition, when sulfur alone is used, heating at a high temperature is required. Therefore, an organic solvent having a high boiling point (for example, a boiling point of 300 ° C. or higher) that can withstand such a high heating temperature must be used. The degree of freedom in selecting an organic solvent is narrow.

  Therefore, in the present invention, by using a highly reactive alkylsilylated sulfur compound for the chalcogenide compound, the reaction can be promoted under low temperature heating, thereby reducing the cost of the chalcogen without complicating the process. It becomes possible to obtain nanoparticles of pyrite type compounds.

  That is, the alkylsilylated sulfur compound is chemically unstable and highly reactive. In particular, Si in the compound easily bonds with sulfur and an alkyl group to easily bond with surrounding oxygen. As a result, sulfur is easily bonded with a cation material.

The case where bistrylmethylsilyl sulfide (((CH ₃ ) ₃ Si) ₂ S) is used as the alkylsilylated sulfur compound is as follows.

Since bistrylmethylsilyl sulfide is chemically unstable and rich in reactivity, as shown by chemical formula (1), Si can contain S or CH ₃ even at a low temperature below a predetermined temperature (for example, 160 ° C.). The structure is easily cut and decomposed to bond with surrounding oxygen (O). As a result, sulfur is easily chemically bonded to the cation, whereby the reaction between sulfur and the cation is promoted even under low temperature heating, and a chalcopyrite type compound can be easily formed.

  As described above, in the present invention, the reaction between the cation raw material and the chalcogenide compound is promoted under low-temperature heating, thereby making it possible to easily produce a chalcopyrite type compound at low cost without incurring complicated processes. .

  Moreover, since the alkylsilylated sulfur compound and the cation raw material react at a low temperature, it is possible to use an organic solvent having a low boiling point for dissolving them, and the degree of freedom in selecting an organic solvent can be expanded. it can.

  Furthermore, the alkylsilylated sulfur compound is inexpensive and non-toxic, and therefore can be easily produced at low cost and low energy without requiring complicated steps.

  In addition, the reactivity can be controlled by selecting the chain length of the alkyl chain, which is an intramolecular functional group, and the particle size and composition control can be improved.

  Such an alkylsilylated sulfur compound is not particularly limited, and bistriethylsilyl sulfide, bistripropylsilyl sulfide and the like can be used in addition to the above-described bistrimethylsilyl sulfide.

  Hereinafter, an example of the manufacturing method of the said compound semiconductor particle is explained in full detail.

  First, two or more kinds of cation materials made of a metal salt are prepared.

  Here, as the cation raw material, two or more kinds of metal salts containing metal elements belonging to the groups Ib to IVb can be used. Various Cu compounds, Ag compounds, Zn compounds, Al compounds, Ga compounds, In Metal salts such as compounds, Ge compounds, and Sn compounds can be used.

Next, a predetermined amount of these two or more cationic raw materials is weighed so as to obtain a final composition. For example, in the case of producing an I-III-VI group ₂ compound, the Ib group element and the IIIb group element are weighed so as to have a molar ratio of 1: 1 to produce an II-III _2- VI ₄ compound. In the case where the IIb group element and the IIIb group element are weighed so that the molar ratio is 1: 2, and the I ₂ -II-IV-VI ₄ compound is prepared, the Ib group The elements, group IIb elements, and group IVb elements are weighed so that the molar ratio is 2: 1: 1. However, the molar ratio is not necessarily a stoichiometric ratio, and may be slightly deviated from the stoichiometric ratio as necessary.

  Then, these weighed cation raw materials are dissolved in the first organic solvent, and the oxygen and moisture are removed under reduced pressure for about 30 minutes at a predetermined temperature (for example, 100 ° C.) to prepare the first solution, Cool to room temperature. Here, the first organic solvent is not particularly limited as long as it dissolves the cation raw material and can withstand the heat treatment described later. The boiling point is a predetermined boiling point (for example, boiling point 170 ° C. or higher). Organic solvents such as aliphatic amines such as oleylamine, alkanes and alkenes having 10 or more carbon atoms, such as decane, undecane, dodecane, tetradecane, octadecane, decene, undecene, dodecene, tetradecene, octadecene, etc. it can.

An alkylsilylated sulfur compound is then prepared and weighed to obtain the final composition. For example, in the case of producing a group I-III-VI ₂ compound, the group Ib element and sulfur are weighed so that the molar ratio is 1: 2, and the II-III ₂ -VI ₄ compound or I _2- In the case of preparing the II-IV-VI ₄ compound, the group IIb element and sulfur are weighed so that the molar ratio is 1: 4. In this case, however, the molar ratio is not necessarily a stoichiometric ratio, and may be slightly deviated from the stoichiometric ratio as necessary.

  Then, these weighed alkylsilylated sulfur compounds are dissolved in a second organic solvent to prepare a second solution. Here, the second organic solvent is not particularly limited as long as it can dissolve the alkylsilylated sulfur compound and can withstand the heat treatment described later. The same material as the first organic solvent is used. Can be used.

  Then, when the first solution and the second solution are mixed and heated at a predetermined low temperature, the chemically silylated and highly reactive alkylsilylated sulfur compound is decomposed, and the chalcogen sulfur is converted into the cation raw material. To form a chalcopyrite type compound. Here, the predetermined low temperature may be a temperature at which the alkylsilylated sulfur compound and the cation raw material react in an organic solvent, and from the viewpoint of expanding the degree of freedom of selection of the first and second organic solvents as much as possible. The temperature is preferably set to 160 ° C. or lower.

  This chalcopyrite type compound is collected as a nanoparticle powder by adding a large amount of organic solvent such as acetone, centrifuging, removing the supernatant, collecting the precipitate and vacuum drying. be able to.

Examples of the chalcopyrite type compound produced include I-III-VI ₂ compound, II-III ₂ -VI ₄ compound, I ₂ -II-IV-VI ₄ compound, and mixed crystals thereof. In this form, since the VIb group element is formed of S, examples of the compound form include the following.

That is, examples of the I-III-VI ₂ compound include CuAlS ₂ , CuGaS ₂ , CuInS ₂ , AgAlS ₂ , AgGaS ₂ , AgInS ₂ , and CuIn _0.5 Ga _0.5 S _{2 in} which CuGaS ₂ and CuInS ₂ are mixed. Can be mentioned. Examples of the II-III ₂ -VI ₄ compound include ZnAl ₂ S ₄ , ZnGa ₂ S ₄ , ZnIn ₂ S _{4 and the} like. Furthermore, examples of the I ₂ -II-IV-VI ₄ compound include Cu ₂ ZnGeS ₄ , Cu ₂ ZnSnS ₄ , Ag ₂ ZnGeS _{4 and the} like.

  As described above, in the present embodiment, the cation raw material composed of a metal salt and the alkylsilylated sulfur compound are reacted in a liquid phase to produce compound semiconductor particles having a chalcopyrite structure. Therefore, the cation raw material and the chalcogenide compound are reduced at a low temperature. The chalcopyrite type compound can be easily produced at low cost without complicating the process.

  Moreover, since the reaction in the liquid phase can be performed under low temperature heating, the energy cost can be suppressed, and a chalcopyrite compound can be obtained without requiring special equipment.

  Further, the mixed solution of the first organic solvent and the second organic solvent is heat-treated at a low temperature of 160 ° C. or lower, whereby the first and second organic solvents have a relatively low boiling point of about 170 ° C. An organic solvent having a boiling point can be used, and the degree of freedom in selecting an organic solvent can be expanded.

  The present invention is not limited to the above embodiment. In the above embodiment, the first solution and the second solution are mixed, and the mixed solution is heated and reacted at a predetermined low temperature to synthesize the cation raw material and sulfur. It is also possible to synthesize the cation raw material and sulfur by heating the solution at a predetermined low temperature and adding the second solution to the heated first solution.

  Next, examples of the present invention will be specifically described.

[Preparation of Example Sample]
First, copper iodide (CuI) and indium iodide (InI ₃ ) were prepared as cation raw materials composed of metal salts, and oleylamine (C ₁₈ H ₂₅ NH ₂ ), which is an aliphatic amine, was prepared as a first organic solvent. .

  Then, 0.4 mmol each of copper iodide and indium iodide are weighed, dissolved in 12 mL of oleylamine as the first organic solvent, and subjected to a reduced pressure treatment at a temperature of 100 ° C. for 30 minutes to remove oxygen and moisture. A first solution was made and cooled to room temperature.

Next, 0.8 mmol of bistrimethylsilyl sulfide (((CH ₃ ) ₃ Si) ₂ S) as the alkylsilylated sulfur compound was dissolved in 8 mL of octadecene (C ₁₈ H ₃₆ ) as the second organic solvent, and the second A solution was made.

  Then, the second solution and the first solution were mixed to prepare a mixed solution, and this mixed solution was heated to 160 ° C., reacted for 1 hour, and cooled to room temperature.

Thereafter, a large amount of acetone was added, and the mixture was centrifuged with a centrifuge at a rotation speed of 167 s ⁻¹ for 15 minutes to perform centrifugation, and the supernatant was removed. Thereafter, a series of steps of adding acetone → centrifuging → supernatant removal was performed three times, and the precipitate was collected and vacuum-dried at room temperature to obtain an example sample.

[Production of Comparative Sample]
A first solution was prepared by the same method and procedure as the above-described example sample, and cooled to room temperature.

  Next, 0.8 mmol of sulfur was dissolved in 8 mL of octadecene to prepare a second solution.

  Then, the second solution and the first solution were mixed to prepare a mixed solution, and this mixed solution was heated to 160 ° C., reacted for 1 hour, and cooled to room temperature.

  Thereafter, a series of steps of adding acetone → centrifuging → supernatant removal was performed four times by the same method and procedure as in the example, and the precipitate was collected and vacuum dried at room temperature to obtain a comparative sample.

(Sample evaluation)
The X-ray diffraction spectrum was measured about the Example sample and the comparative example sample.

  FIG. 1 is an X-ray diffraction spectrum of an example sample, and FIG. 2 is an X-ray diffraction spectrum of a comparative example sample. In the figure, the horizontal axis represents the diffraction angle 2θ (° C.), and the vertical axis represents the X-ray intensity (a.u.).

  As shown in FIG. 2, the comparative example sample did not produce a significant peak indicating the presence of the specific element in the X-ray diffraction spectrum, was in a broad state, and it was found that the desired chalcopyrite compound could not be produced.

On the other hand, in the example sample, as shown in FIG. 1, peaks indicating the presence of Cu, In, and S appear in the X-ray diffraction spectrum, and it was confirmed that a chalcopyrite compound of CuInS ₂ was prepared. . Moreover, it was 10-50 nm when the particle size of the Example sample was confirmed with the scanning electron microscope (SEM).

  A chalcopyrite type compound semiconductor can be easily obtained by heat treatment at a low temperature, which can contribute to an improvement in productivity.

Claims (7)

  A method for producing compound semiconductor particles, comprising reacting two or more kinds of cation raw materials comprising a metal salt with an alkylsilylated sulfur compound in a liquid phase to produce compound semiconductor particles having a chalcopyrite structure.   The method for producing compound semiconductor particles according to claim 1, wherein the reaction in the liquid phase is performed under low temperature heating of 160 ° C. or lower.   The cation raw material is dissolved in a first organic solvent to prepare a first solution, and the alkylsilylated sulfur compound is dissolved in a second organic solvent to prepare a second solution. The method for producing compound semiconductor particles according to claim 1, wherein a mixed solution is prepared by mixing the solution and the second solution, and the mixed solution is heat-treated at a predetermined low temperature.   The cation raw material is dissolved in a first organic solvent to prepare a first solution, and the alkylsilylated sulfur compound is dissolved in a second organic solvent to prepare a second solution. The method for producing compound semiconductor particles according to claim 1, wherein the solution is heated at a predetermined low temperature, and the second solution is added to the heated first solution.   The method for producing compound semiconductor particles according to claim 3 or 4, wherein the predetermined low temperature is 160 ° C or lower. The chalcopyrite structure, I-III-VI ₂ group of the Periodic Table, II-III ₂ -VI ₄ group is composed of elements belonging to I ₂ -II-IV-VI ₄ group, an element belonging to Group VI The method for producing compound semiconductor particles according to claim 1, wherein the compound semiconductor particle is sulfur.   The method for producing compound semiconductor particles according to any one of claims 1 to 6, wherein the alkylsilylated sulfur compound contains bistrimethylsilyl sulfide and bistrylethylsilyl sulfide.

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