TW201208103A - Nanostructured solar cell - Google Patents

Abstract

Systems and methods for fabrication of nanostructured solar cells having arrays of nanostructures are described, including nanostructured solar cells having a repeating pattern of pyramid nanostructures, providing for low cost thin film solar cells with improved PCE.

Description

201208103 The patterned layer has a nanostructure on it. 2B to 2E illustrate top views of an embodiment of a nanostructure. Figures 3 to 6 show simplified side views of an embodiment of a nanostructure solar cell formed in accordance with the present invention. Figure 7 shows a simplified side view of a patterned layer wet etch to increase the relative height of the nanostructure. 8A-8B illustrate a simplified side view of a patterned layer of a solar cell. 9A to 9C illustrate a simplified side view and a plan view of one of the solar cells as an example of a nanostructure pattern. 10A to 10C illustrate one example of forming a texture fine structure in a conductive layer. Figure 11 shows a simplified side view of one embodiment of a nano-solar cell having a fine texture in a conductive layer. Figure 12 is a simplified perspective view of another embodiment of a nanopattern substrate for use in a thin film solar cell formed in accordance with the present invention. Fig. 13 is a top plan view showing a section of the nano pattern substrate of Fig. 12. Fig. 14A is a simplified side view showing a section of the nanopattern substrate of Fig. 12. Fig. 14B is a simplified side elevational view showing one of the sections of the nanopattern substrate of Fig. 14A. Figure 15 is a simplified side elevational view of one embodiment of a nanopatterned thin film solar cell formed in accordance with the present invention. 201208103 Figure 16 shows a simplified side view of another embodiment of a nanopatterned thin film solar cell formed in accordance with the present invention. Fig. 17 is a block diagram showing an exemplary system for forming the nano pattern thin film solar cell of Fig. 15. Fig. 8 is a block diagram showing an example system for forming a nanopattern thin film solar cell of Fig. 16. 19A to 19C illustrate an exemplary template for the use of a nano pattern substrate for forming a thin film solar cell. 20A to 20C illustrate an exemplary template for forming a nano pattern substrate of a thin film solar cell by using a positive force. 21A to 21D illustrate a scanning electron micrograph of the nano-patterned solar cell of the nanopattern 4 solar cell shown in Fig. 6. Fig. 22 shows an electron micrograph of a nano-pattern thin film solar cell similar to the solar cell shown in Fig. 6. Fig. 23 is a view showing another scanning electron photo of a nano pattern thin film solar cell similar to the solar cell shown in Fig. 6. Figure 24 25 shows a simplified side view of a nanopatterned thin film solar cell embodiment having a nanostructure with a loosened surface. Figures 25 to 26 show scanning electron micrographs of a nano-patterned film layer having a nanostructure having a roughened surface. t embodiment; J. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT When compared with crystalline germanium (C-Si) in photovoltaic modules, thin film amorphous germanium (such as a-Si) has low cost and is generally Compatible with roll-to-roll processing (ie strip 6 201208103). However, a-Si based solar cells are generally subject to lower energy versus efficiency (PCE). For example, current a-Si based solar cells can have a conversion efficiency of between about 4.5 and 8.5%. Usually a ratio of about 10 is required. /. Larger PCEs can compete with commercially available solar cells (such as C-Si, GaAs, etc.). In addition, currently designed a-Si based solar cells are less stable than commercial C-Si solar cells. Although thin solar cells can be cost effective, they have lower efficiency and/or lower deposition rates. Therefore, its formation may involve a longer lag time for a film which can deposit even Ιμιη. Further, the thin film tantalum solar cell is similar to the solar cell 6 〇 and can only achieve an efficiency value of about 1%. In terms of production mode, this efficiency may even be reduced by many actual reduction factors. Therefore, the actual efficiency value may be only about 6 to 7%.

Some resources show that the ability to provide nanostructured materials at a reasonable cost can significantly enhance the efficiency of solar cells. This concept is discussed in: Fontcuberta i Morral, Α., R Roca i Cabarrocas et al. "Structure and Hydrogen Content of Polymorphic Thin Films by Spectroscopic Ellipsometry and Nuclear Measurement" Physical Review B Condensed Matter and Materials Physics 69(12): 125307/1-125307/10 (2004); Liao, X., W. Du et al. "The effect of the nanostructures in the p and i layers on the performance of amorphous tantalum solar cells. Phis, Z., S.-T. Chang et al. Numerical Simulation of Playing Behavior UIEEE Electron Device Letters 30(12): 1305-1307 (2009) ; A 201208103

Shih, H.-F., S_-J. Hsieh et al. "Improvement of the light trapping effect of a disc using a wavelength structure" Applied Optics 48(25): F49-F54, (2009), their contents are This is included. The nanostructure reduces the travel distance of the excitons and provides sufficient light absorption. Moreover, the a-Si layer having a nanostructure can have higher stability. See Fontcuberta. The use of a thin a_si layer also reduces deposition time and/or cost. Currently in the field, providing a nano-structured solar cell is a difficult route. For example, '(http://www.technologyreview.com/energy/24547/pagel/) Solasta uses microsphere lithography to form a pattern of crystalline metal (nickel) and deposits carbon nanotubes (CNTs) on top. However, this method lacks control over the size of the column' and generally proceeds lengthily. In another example, Fan et al. grew a column of nanoparticles on a substrate. See Fan et al., "Three-Dimensional Nanopillar Array Photovoltaic Devices on Low Cost and Flexible Substrates" Nature Materials, Vol. 8, 648-653 (2009), the contents of which are hereby incorporated. Aluminum stencils can be obtained by anodization. However, these methods are generally expensive, the size of the nanostructures may be difficult to control and/or the interface between layers may be less prone to result in a lower PCE if compared to a flat solar cell. Therefore, it would be too expensive to grow a nanocolumn array for manufacturing, as compared to commercially available solar cells. Referring to Figures 1 to 3, a nanostructure solar cell 100 can be used to provide a low cost option and a large stability of nanoimprint lithography, which is produced at a low cost in a high PCE. Typically, the fabrication of the nanostructured solar cell 100 can include a low viscosity UV curable imprint fluid and/or a fluid dispensed as needed. The choice of fluid and fluid volume may depend on the pattern density of an imprint template 118. Imprint template 118 can form a patterned surface 146 having nanostructures 〇5〇 and 152 formed by formable material 134, and the like. Amorphous germanium (a-Si) germanium can be deposited on the nanostructures 150 and 152. Nanostructures 150 and 152 increase the surface area of the contact. The nanostructures 150 and 152 can also be designed to facilitate light trapping, which increases the absorbance while maintaining a small exciton shift distance. Referring to Figures 1 and 2, photolithography system 100 can be used to form a relief pattern on substrate 112. Substrate 112 may be formed from a hard, transparent material including, but not limited to, poly(p-butylene phthalate) (PET), polyethylene naphthalate (PEN)' and/or the like. The substrate 112 can be lightly attached to the substrate chuck 1丨4. As shown, the substrate chuck 114 is a vacuum chuck. However, the substrate chuck 114 can be any chuck including, but not limited to, vacuum, plug, groove, electrostatic, electromagnetic, and the like. An example of a chuck is disclosed in U.S. Patent No. 6,873, the entire disclosure of which is incorporated herein by reference. Substrate 112 and substrate chuck 114 are in turn supported by stage 116. Stage 116 can provide translational and/or rotational motion along the X, y, and z axes. The stage 116, the substrate 112 and the substrate chuck 114 can also be placed on a base (not shown). Separate from the substrate 112 is a template 丨丨8. The template 8 may include a body having a - face and a second face having a boss 12 projecting therefrom toward the substrate 112. The boss 120 has a patterned surface 122 thereon. Further, the convex σ 120 may also be referred to as a -modulo 12 〇. Alternatively, the template 118 can be made without the bosses 120 〇° 9 201208103 The template 118 and/or the mold 120 can be formed from materials including, but not limited to, fused ceria, quartz, ruthenium, organic polymers, A siloxane polymer, a borosilicate glass, a fluorocarbon polymer, a metal, a hardened sapphire, and/or the like. As shown, the patterned surface 122 includes a thin structure or the like defined by a plurality of spaced apart recesses 124 and/or protrusions 126, although embodiments of the invention are not limited to such configurations. The patterned surface 22 can define any original pattern that will form the basis of a pattern to be formed on the substrate 112. The template 118 can be coupled to the chuck 128. Chuck 128 can be constructed, but is not limited to, vacuum 'plug type, groove type, static electricity, electromagnetic type, and/or other similar chuck type. An example of a chuck is also disclosed in U.S. Patent No. 6,873,087, the disclosure of which is incorporated herein. Also, the chuck 128 can be coupled to the stamping head 130 such that the chuck 128 and/or the stamping head 130 can be configured to facilitate movement of the template 118. System 110 can further include a fluid dispensing system 132. The fluid dispensing system 132 can be used to deposit a formable material 134, such as a polymerizable material, onto the substrate 112. The formable material 134 can be disposed on the substrate 112 using techniques such as dropping, spin coating, dip coating, chemical vapor deposition (CVD), physical vapor deposition (PVD), thin film deposition, thick film deposition, and the like. Imprinting of variable pattern densities can be performed by dispensing as needed, with minimal chemical and mechanical waste. In addition, there is no need for a special double-sided spin coater. The dispensing method by drip cloth as needed is generally considered to be cleaner than the spin-on deposition. Again, a very thin and substantially uniform residual layer thickness can be achieved as needed, as described in more detail below. The formable material 134 can be deposited on the substrate 112 before and/or after a desired volume is defined between the die 22 and the substrate 10 201208103 112, depending on design considerations. The formable material 134 can be a functional nanoparticle having utility in the solar cell industry, and/or in other industries where a functional nanoparticle is required. In one example, the formable material 134 can comprise a monomer mixture as described in U.S. Patent No. 7,157,036, issued to U.S. Pat. Alternatively, the formable material 134 can include, but is not limited to, solar cell materials, and/or the like. Referring to Figures 1 and 2, system 110 can further include an energy source 138 coupled to direct energy 140 along path 142. Imprint head 130 and stage 116 can be configured to position template 118 and substrate 112 in path 142. System 110 can be regulated by processor 154 to communicate with stage 116, stamping head 130, fluid dispensing system 132' and/or energy source 138, and can be operated by a computer readable program stored in memory 156. One or both of the stamping head 130 and the step 116 will change the distance between the die 120 and the substrate 112 to define a desired volume therebetween, which will be filled by the formable material 134. For example, the stamping head 130 can apply a force to the template 118 to contact the mold 120 with the formable material 134. After the desired volume fills the formable material 134, the energy source 138 generates energy 140, such as ultraviolet radiation, to cure and/or crosslink the formable material 134 to conform to the surface 144 of the substrate 112 and the patterned surface 122. The shape 'defines a patterned layer 146 on the substrate 112. The patterned layer 146 can include a residual layer 148 and nanostructures 150 and 152, etc., the nanostructure 150 has a thickness q, and the residual layer has a thickness t2. Nanostructures 150 and 152 may vary in size and/or have a different shape 201208103 including, but not limited to, a straight line 'column, hole, pyramid or any odd shape. The microstructure height may generally be at least about 10 nm, or at least about 5 m, or at least about 1 μm. The nanostructures in the smectic industry tend to be formed by carbon nanotube columns and the like, and thus the provision of complicated structures is generally expensive. However, nanoimprint lithography provides tunable denaturation at low cost to provide the ability to optimize the shape of the nanostructure. In this regard, the size and shape of the nanostructures 15 and 152 can be designed to optimize the solar cell. The size and shape configuration can be based on (1) specifying a depth for one of the nanostructures 150 and/or 152 to maximize the choice of a-Si volume spacing, shape and aspect ratio; (2) maximizing light trapping Capture rate; and/or (3) maximum stability before and after the button engraving process. 2B to 2E show an embodiment of the nanostructures 150 and 152 used in the solar cell 1 and the like. Referring to Figure 2B, it is shown that the nanostructures 150a and 150b can be formed into a straight line. The length and arrangement (e.g., pattern) of lines 150a and 150b provides stability. For example, the straight line 150a and the straight line 150b may be substantially similar in size and disposed at an angle to each other. As shown, the line 150a is disposed at a 90 degree angle with respect to the line 150b. Although shown as a 90 degree angle, the lines 150a and 150b can be set at any angle that provides stability. Referring to Figure 2C, the nanostructure 150 can be used to extend the portion 151 and a pillar formation 153. The extension portion 151 can be a substantially linear formation of a joint post 153 or the like. Alternatively, the straight line 155 may be interconnected with adjacent columns 153, and a box-like pattern 12 201208103 157 is formed between the extension 151, the post 153 and the line 155. The line 155 can have a size that is substantially smaller than the extension 151. The fine dimensions of the nanostructures 150 and 152 can be pre-biased in accordance with a predetermined size reduction during the etching process. For example, Figure 2D shows a cross pattern former of a nanostructure 150 before and after etching. The nanostructure 150 can be pre-biased in consideration of this reduction. Similarly, the nanostructure 150, which is shown as a pillar formation as shown in Fig. 2E, can be pre-biased in consideration of the size reduction in the case of insects as described in more detail herein. The above system and method can also be applied to the imprint lithography method and system in the following U.S. patents: No. 6,932,934, No. 7,077,992, Ν〇· 7,179,396, and No. 7,396,475, etc., the contents of which are hereby incorporated by reference. . A roll-to-roll method can be developed with limited variations in the process and tools. When a flexible substrate is used, the stamping station can be incorporated into a roll-to-roll system. The substrate is unwound from a roll, then patterned by embossing, and finally reeled onto another roll. The roll-to-roll method is highly productive and can operate at lower cost. Referring to Fig. 3, after the nanostructures 150 and 152 are formed on the substrate 112, a transparent conductive oxide layer (TC layer) 160 may be disposed on the patterned layer H6. The TCO layer 160 can be deposited by evaporation, CVD, sputtering, or the like. Typically, the TCO layer 160 can be deposited at a target temperature below 200 ° C or less than the degradation temperature of the underlying layer. The TCO layer 160 can be formed of materials including, but not limited to, indium tin oxide, zinc oxide, tin dioxide, and the like. In general, acceptable materials for the TCO layer 160 comprise materials having a high electrical conductivity and balanced solar transmittance. The TCO layer 160 typically contains a low sheet resistivity 'e. e.g., about 13 201208103 100 ohm/sq or less. The thickness of the TCO layer 160 can range from about 50 nm to 250 nm. Depositing the TCO layer 160 on the patterned layer 146 forms a front electrode. An active layer 162 can be deposited on the TCO layer 160. The active layer 162 may be a three-layer (p-i-n) a-Si: i.e., a-Si p layer 16 a a-Si intrinsic layer 163, a-Si η layer 165. The active layer 162 can be deposited by PECVD, LPCVD, HWCVD or the like. Generally, the active layer 162 can be deposited at a temperature of about 200 ° C or a temperature lower than the degradation temperature of the underlying patterned material. The nanostructures 150 and 152 of the underlying patterned layer 146 eliminate the "thick," and "thin" compromises typically found in thin film solar cell designs, and separate the path of electrons from the path of photons. For example, thicker The active layer 162 has more incident light that can be collected, and more free electrons can be generated. However, if the thickness is increased, less free electrons can be efficiently sent out. The placement and design of the meters 150 and 152 provides an increased surface area while minimizing the distance at which free electrons are sent. Again, the degradation of a-Si may depend on the thickness of the intrinsic layer 163. For example, the thickness is A solar cell of 100 nm or less generally does not have significant deterioration compared to a thicker size. Thus, the thickness of the intrinsic layer 163 can be configured to be in the range of about 80 nm to 200 nm, and the p layer 161 can be The composition is in the range of about 5 nm to 20 nm, and the n layer 165 can be configured to be in the range of about 5 nm to 40 nm. The design of the patterned layer 146 can be configured to provide a high aspect ratio to increase activity. The absorption capacity of layer 162 remains thick The aspect ratio may be between i and 3 or may be between 1 and 1 〇 or more. In one example, the height of the nanostructure 14 201208103 150 may be in the range of about 500 nm to 100 nm or more. In another example, the pitch may be between about 500 nm and 2 μm or more, and the nanostructure 150 has a width of from 25 nm to 300 nm or more. A rear reflective layer 16 4 may be deposited to form a nanostructured solar energy. The active layer 162 of the battery 100. The back reflective layer 164 may be formed of materials including, but not limited to, silver, silver, and the like. In general, acceptable materials for the back reflective layer 164 may include highly reflective Rate and conductivity material. The back reflection layer 164 can be deposited using techniques including evaporation, sputtering, cVD, etc. The thickness of the back reflection layer 164 can be configured to provide good conductivity 'eg, from 30 nm to In addition, the thickness of the back reflection layer 164 can be designed to provide protection of the solar cell 100 in the event of environmental attack. The back reflection layer 164 can reflect light to the active layer 162. Further, the back reflection layer 164 By corresponding to An electrical smash effect of the size and/or shape of the surface tissue traps light having a particular range of wavelengths. An anti-reflective layer 170 is optionally disposed adjacent to the substrate 112 (e.g., deposited on the substrate 112) The anti-reflective layer 170 may be formed of a material having anti-reflective properties and capable of transmitting incident light. The thickness of the anti-reflective layer 17A may be between about 10 nm and 200 nm. - The buffer layer 172 (eg, doped zinc oxide) may be reversed The anti-reflection layer 170 is directly disposed on the solar cell 10〇3 as shown in Figures 3 to 4. For example, the buffer layer 172 may be disposed between the rear electrode 164 and the active layer 162. The thickness of the buffer layer Π2 can be made thin enough to contact the metal's electro-converescence effect and cause stress in the _ film layer, but thick enough to sufficiently block the hole of 201208103 § hai (for example, 3〇nm~100mn). Buffer layer 172 can help collect electrons' and prevent atoms from diffusing between layers 164 and 162. In addition, a second buffer layer (e.g., pc-Si) may be deposited in addition to the a-Si p layer to assist in the collection of holes. Fig. 4 is a view showing a variation of the nanostructure solar cell 1 〇 shown in Fig. 3, which is shown as a nanostructure solar cell 100a. The nanostructure solar cell 10a can have more active material than the same patterned layer 146a. Typically, a first TCO layer 160a can be deposited on the substrate 112. The patterned layer 146a can be formed on the first TCO layer 160a using the methods and systems described in relation to Figures 1 through 2. The recessed regions 166 of the patterned layer 146a can be exposed to a desmearing etch. An etch process (e.g., VUV slag removal) removes the photoresist in recessed region 166 to expose 160a. The exposed region of TCO layer 160a can deliver charge. Photoresist etching can be performed in a low cost manner, such as VUV slag removal, which is compatible with roll-to-roll processing. A second TCO layer 160b and/or a metal layer (e.g., 10 nm of titanium) may be deposited on the patterned layer 146a. The second TCO layer 160b can assist in conducting, for example, the charge generated by the active layer 162 at the top end 168 and/or sidewall 174. The TCO layer 160b can be configured to be sufficiently thin that it can provide substantially good conductivity without taking up too much space and substantially not absorbing incident light'. The active layer 162 can be deposited on the TCO layer 160b. The optional selection of the nanostructured solar cell 1 (shown in Figure 3) should also be incorporated into the design of the nanostructure solar cell 100a. Fig. 5 shows a variation of the nanostructure solar cell 100 shown in Fig. 3, which is shown as a nanostructure solar cell 100b. It should be noted that the optional selection of the nanostructure solar cell 100 shown in Fig. 3 201208103 can also be incorporated into the design of the nanostructure solar cell 100b. The nanostructure solar cell 1〇〇b is roughly designed as one of the reverse structure of the nanostructure solar cell 100, and the patterned layer 146b having the nanostructure 150b is formed on the substrate 112a. However, the substrate 112a of the solar cell 100b is not necessarily transparent because it is not in the path of sunlight. Conductive layer 164b is formed over patterned layer 146b, followed by buffer layer 172b' active layer 162b and TCO layer 160c. Metal contacts 167b can be formed on the TCO layer 160c. Fig. 6 is a view showing a variation of the nanostructure solar cell 10a shown in Fig. 4, which is shown as a nanostructure solar cell 100c. It should be noted that changes in the nanostructure solar cell 1 〇 shown in Fig. 4, for example, the nanostructure solar cell 100a can be incorporated into the design of the nanostructure solar cell 100c. The nanostructure solar cell 100c is roughly a reverse design of the nanostructure solar cell 100a. In summary, the solar cell i〇〇c can include a conductive layer 180 and a patterned layer 146c formed thereon. The residual layer of the patterned layer 146c can be etched away as previously described, leaving the nanostructures 15 as such. The buffer layer 172c, the active layer 162c, and the TCO layer 160c are formed on the nanostructure 丨5〇c, and the metal contacts 167 may be formed on the TCO layer 160c. The conductive layer 18 can be formed of materials including, but not limited to, silver that does not rust or a metal that is coated with glass or a plastic polymer such as PET, PEN, or inorganic materials such as clay and ceramics. , or other conductive materials, etc. Fig. 7 shows a variation of the solar cells 1a and 100c in which wet etching of the conductive layer 18 0 increases the relative height of the nanostructures 丨5 由 from h ^ to 17 201208103 h. Wet etching can produce a concave shape in the conductive layer 18 by using an acidic solution. The wet etch is generally isotropic and may have a significant undercut enlargement opening area or the like in the conductive layer 18A. However, this incision can be estimated and incorporated into the line width. In one example, as shown in FIG. 8, the patterned layer 146 can be deposited on top of the conductive layer 借8 by nanoimprint. The patterned layer 146 can be configured to have a width substantially equal to the size of the L i plus the undercut (eg, 2 χ etch depth = a wet etch layer 182 can be deposited between the conductive layer 180 and the patterned layer 146). The wet etch layer 82 can have a fast etch rate and/or a preferred etch profile compared to 180. Here, the undercut can be severe and the initial straight line or other fine structure can be much larger than that left after etching. An adhesive layer is optionally required to provide better adhesion to the patterned layer 146 or the conductive layer 18 or both. Further, a surfactant may be added. Considering the reverse cut during wet etching, The initial straight line can be preset to be thicker, which can result in a reasonably fine nanostructure 150 (such as a wire or column) after etching. Wet etching can be increased by its low cost and compatibility with the roll-to-roll method. The height and aspect ratio are formed, but etching into the conductive layer 180, or otherwise etched into the non-conductive substrate, may not be limited to wet etching. If appropriate, other etching methods such as dry etching may also be used. Imprint lithography as shown in Figures 1 and 2 Typically, a profile pattern is copied from the template 118 to a formable material 134 between the template 丨 18 and the substrate 丨 12. When embossed, the spacing of the stencil 118 from the substrate 112 can be reduced and The forming material 134 will flow to conform to the profile of the template ι 8 and the substrate 112. When the stencil 118 is very close to the ride 112, the flow path of the formable material 134 is narrow and, therefore, the flow is limited. 18 201208103 This can be improved if the formable material 13 4 is formed from a low-viscosity material (for example, a material having a viscosity of less than 1 〇 centipoise). A low-viscosity material is available for a flow of about 25 nm or less. Between the channels, the thickness of the runner will generally provide the thickness of the residual layer 148. As a result of the deformation flow, the residual layer 148 having a non-zero thickness will always appear after being imprinted in the formable material 134. The most common method of removing the residual layer 14 8 is to perform a plasma-based etching process which is capable of directional (i.e., predominantly vertical) etching, allowing the residual layer 148 to be removed, and the nano Landscape of structure 150 There is only minimal change in inch. However, plasma etching may not be suitable for the formation of batteries 100 to 100d provided herein because of certain factors such as high cost, low throughput, and/or low pressure environment. As a variant, A vacuum ultraviolet (VUV) process can be used to remove the residual layer 148 in the solar cell and/or the underlying organic layer formed by non-imprinting. In general, the VUV process will be in a controlled composition. The material is exposed to radiation from a source in a gaseous environment. The light radiation of νυν can be a wavelength between about 120 nm and 190 nm. The radiation can be caused by using an xe excimer dielectric barrier discharge lamp, which has an The peak intensity at 172 nm and a spectral bandwidth of approximately 15 nm FWHM. In one example, the light intensity at the surface of the material can be about 5 to 15 〇 nW/cm 2 . The gas becomes at least 95% rat and less than 5% oxygen. The νυν process can also be used to remove the underlying organic layer from the pattern formed by the non-imprint method. VUV processes can also be used to etch inorganic materials. When the inorganic material is etched, the gas component can be changed by those used for the organic material. For example, a gas-containing gas mixture can etch materials such as copper and gallium arsenide. See Li et al., 201208103

Appl· Phys_ A, Vol 57 p 457 1993, Streller et al., gossip 1.811 ratio

Sci. vol. 109/110, p 442 1997; its contents are hereby attached. The ruthenium layer can be etched in a gas mixture containing fluoride such as XeF2. See Streller et al. 'Appl. Phys. Lett, vol 69 p 3004 1996 ’ for details. In some embodiments, the νυν process can be followed by a liquid processing step to further improve the etching results. For example, Sic can be exposed to VUV light first.

The crucible is immersed in an aqueous solution containing HCl and Η2〇2 and immersed in an aqueous solution containing HF to be etched (see Zhang et al., Appl. Phys. A. vol 64, p 367, 1997^ in this example, The aqueous solution will assist in the removal of the ν υ 曝光 曝光 曝光 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 The capacity can be determined by a number of factors, including substrate surface strength, material removal rate, material thickness, etc. Therefore, it may be preferable to minimize the thickness of the material to be removed, as this may add to the vuv process. Capacity - For imprint lithography, this may require embossing with a very thin residual layer. However, with a very thin residual layer embossing, all pattern types are not straightforward. The residual layer of the material becomes very 4, and the flow through the -Hai channel will be more and more restricted, as described above. The limitation of this flow can be minimized by the friction of the case at the level of the residual layer. Minimized. In the example, as shown in Figure 8 The nanostructure pattern 146 can be designed to be a sparse _, that is, the nanostructure 丨 _ width is substantially smaller than the distance 奈 5 2 between the nano and σ structures, and in some cases is less than the distance 2~ 3 20 201208103 times. In this pattern, the thickness t2 of the residual layer 148 may be substantially larger. When the residual layer U8 is removed, the patterned layer 146 may be exposed to the wv process to eliminate the residual layer 148, such as the first However, it may take a long time, because k is thicker, and its productivity may not be high. Referring to Figures 9A and 9B, a modification of the process may include forming a patterned layer 146 with additional The stepped pattern 147 is adjacent to the nanostructure. To define - even a thinner residual layer 148a overlying the small area (10) of the patterned layer (10). Contact to the underlying substrate 112 can be removed only by the patterned layer The residual layer 14 at region 149 of 146 is reached as shown in Fig. π, and the entire thickness of the residual layer, vvuv (4), is improved by reducing the thickness of the removed material. In addition, the 'vuv exposure time will Reduce the harmful effects of VUV exposure on the surface of the nanostructure For example, see Figure 9C. 'Nano structure 15〇, etc. can be recorded, as shown by the circle, and supplement the contact hole 149, etc.' as shown by the dark circle. In this design, the area density of the contact hole (4) It may be sufficient to reduce the contact resistance, but will provide a very thin residual layer 148a to be easily removed by the VUV process. See Figure 13 to Figure 18 for the solar cell TC layer 160 and/or The conductive layer 18 is optionally patterned using the methods and systems described in relation to Figures 1 and 2. - The textured surface having tissue textures 15Ga and 152a, etc., reduces light reflection. Again, a well-defined pattern on the conductive layer 18〇 increases light scattering' and enhances the plasmon effect to increase light trapping. The dimensions of the optimal tissue textures 150a-152a (e.g., shape, depth, aspect ratio) may vary relative to the dimensions of the nanostructures 150 and 152, etc. provided in Figures 3-6 (e.g., may be non-sparse And / or the aspect ratio can be much lower, such as about 1: 1: 21 201208103 or even lower). Patterning of conductive layer 180 can excite surface plasmon (sp) effects at the interface of the metal/semiconductor (eg, metal/Si, metal/ITO, metal/ZnO, etc.) and efficiently trap/guide light To the active layer 162. In this regard, a thinner active layer 162 may be sufficient for light absorption and/or light trapping, and thus "thinner, the film may comprise, for example, better charge collection" less recombination and shorter exciton migration. In addition, a thin film can reduce the dark current, increase the open circuit voltage, etc. The SP effect is generally applied to the interface, but the attenuation through the index may affect hundreds of nanometers. At a metal dielectric interface (such as Ag/Si〇2), the intensity of the light field at a resonant wavelength can be as high as 1〇〇. The t-wavelength can be tuned by changing the pitch size and metal/dielectric material. The incident solar stream can be effectively rotated up to 9 〇. and the light can be absorbed along the lateral direction of the solar cell, having a size greater than the vertical length (active layer thickness). For example, in a simulation Among them, a nano-pattern fine structure 150a' having a pitch of about 180 nm has Ag as a back reflection layer and has a germanium pattern and an a-Si layer, showing that a maximum enhancement of 98.8 times is achieved at a resonance wavelength of 8 〇〇 nm. Although when When the wavelength is shifted by a sharp peak (such as 8 〇〇 nm), the enhancement coefficient will decay rapidly, but the overall enhancement in the visible and near-infrared regions (from 400 to 100 nm) is very significant, at 9 〇〇 nm. 66 times, 15 times in lOOOnm, 22 times in 700nm, and 6 times in 500nm. For a TCO layer, the fineness of the nano pattern can be determined according to the structure of the solar cell, the optical properties and thickness of the active layer. The required optical resonant wavelength (eg, tandem solar cells with different band gaps can absorb and convert different portions of the sun 22 201208103 light). The solar cell 100 shown in Figures 3-6 ~100c may further comprise organized textures 150a and 152a of TCO layer 160, etc., and/or conductive layer 180 to further increase PCE. This may include one or more additional steps by adding patterned TCO layer 160, after The reflective layer 164, or both, forms the solar cells 100 to 100c. FIGS. 10A-10C illustrate an embodiment in which the formation of a sparse pattern of the active layer 162 and further patterning of the TCO layer 160 or the conductive layer 182 are deposited. Can be done in a single lithography step. The design of template 118 (shown in Figure 1) can be provided to imprint functional material 134 having tissue textures 150a and 152a and nanostructures 150d, as shown in Figure 10A. Nanostructures 150d and tissue The residual layers of the features 150a and 152a may be removed by VUV or other methods. Wet etching or other suitable etching may be performed to etch the exposed conductive layer 180d by trenches 152a, etc., as shown in FIG. 10B. A second desmear process can remove the formable material (i.e., photoresist) for subsequent deposition, as shown in Figure 10C. Thus 'increased PCE can be obtained at minimal cost. Figure 11 shows the example 1 〇〇d of a nano-structured solar cell, which is similar in design to a solar cell 10c (shown in Figure 6), and a patterned conductive layer 18 is added. 〇d. In addition to the nanostructure 150d, the nanopatterned conductive layer 180d contains regions of tissue texture 150a and 152a that can assist in trapping more light by SP and surface scattering, resulting in an even more solar cell 100c High PCE. Other organization of the nanostructure can also be performed to increase PCE. Example 23 201208103 For example, the surface energy forming the nanostructure can be processed to exhibit an increased thickness. This rough surface will increase the amount of light scattering and trapping, resulting in a well-changed PCE. The coarse-grained structure can be randomized and the fine-grained size can be substantially smaller than the fine-grained size of the main pattern. The rough tissue can be incorporated into the embossing stencil such that the roughness can be transferred directly from the stencil to the photoresist of the embossed portion. Alternatively, the roughness can be caused by dry etching. When dry etched, under certain conditions, a polymer or other material can be deposited on the samples to form a micro-mask. This micro-mask effect can cause the surface of the etch to be rough. Figure 26 shows a dry etched glass having a rough surface 5 5 丨a on a regularly patterned (larger) pyramidal nanostructure 550a. This roughness can also be caused by depositing a #膜 on the template or directly on the patterned surface of the solar cell. In some cases, the deposited film can be granular: it can be a secret. Figure 27 is a SEM image showing the deposition of a coarse ITO film on a patterned glass substrate having a pyramidal structure 5 turns, resulting in a tantalum surface 551be shown in Figures 12, 13 and 14-8-14B for solar cells. Further embodiments of the nanostructure, particularly the angular hybrid structure 25G', have been shown in detail to have improved light trapping characteristics. 13#〇ΐ4Αϋ * 排列 Arrange the in-line and horizontal rows f at a pitch p and a distance d between the bases of adjacent pyramids. The height h can generally be at least about 100 nm, or at least 500 nm, or at least 1 μΐΏ. In some aspects, the height h can generally be in the range of 150 to 100 nm. The pitch p can generally be at least about 2 〇〇 nm, or at least about Ιμηη, or at least 2 nm. In some aspects, the spacing? _ can be in the range of 3 〇〇 nm to 600 nm. The pyramidal nanostructure 25 has a square base 24 201208103, as shown, but the bases may equally be other polygons or circles. The angle 0 between the surface 152 and the tapered surface 154 of the pyramidal nanostructure may generally be at least 100, or at least 135. , or at least 15 weeks. , or at least 170. . In some aspects, the angle 0 can range from 11 150 to 150 degrees. In addition, the overall fine dimensions of the pyramidal nanostructure 250 can be pre-biased depending on the size reduction known in one of etching and/or mating addition layers and/or imprinting processes. As shown in Figures 14A-14B, the intersection between the surface 252 and the base of the pyramid can be arcuate. This arcing can be achieved in a number of ways, including by etching and/or imprinting techniques, etc., as further described below. This rounded sonication pattern is important for the stability and improved performance of the additive material that coats the substrate to form the solar cell. In particular, a conductive material coated on a patterned substrate having sharp corners is susceptible to strain and cracking, thereby damaging the conductive material and reducing battery performance. By arcing the intersection of the surface and the base of the pyramid, the conductive material can be deposited on the patterned surface and will maintain its integrity throughout the pattern, resulting in improved performance. Referring to Fig. 15, the solar cell 200 can be formed as described above after the pyramidal nanostructure 250 is formed on the substrate 212. The first conductive material 264 can be deposited on the substrate 212. The first conductive material 264 may be formed of materials including, but not limited to, aluminum, silver or the like. In general, acceptable materials for conductive material 264 comprise materials having high reflectivity and electrical conductivity. The electrically conductive material can be applied directly to the substrate 212, or alternatively an adhesive layer (not shown) can be applied between the substrate 212 and the electrically conductive material 264 to promote the interface between the substrate 212 and the electrically conductive material 264. Adhesive. Materials suitable for the adhesive layer include, but are not limited to, Ni and Cr. The adhesive layer and conductive material 264 can be deposited using techniques including evaporation, sputtering, CVD, and the like. The thickness of the conductive material 264 can be configured to provide good electrical conductivity, for example, in a range from 30 nm to 200 nm or more. In addition, the thickness of the conductive material 264 can be designed to provide protection for solar cell 2 degradation against the ring. The electrically conductive material can reflect light to the active layer 266. In addition, the electrically conductive material 264 can trap light having a particular range of wavelengths by an electromeric effect corresponding to the size and/or shape of its surface tissue. A semiconductor layer 262 can be deposited over the conductive material 264. The semiconductor layer 262 can be a three-layer (p-i_n) a-Si layer: a_Si? layer 261, a Si intrinsic layer 263, a_Si n layer 265, and the p layer is typically oriented closest to the source. The semiconductor layer 262 can be deposited by PECVD 'LPCVD, HWCVD, or the like. In general, the semiconductor layer 262 can be deposited at a temperature of about 200 ° C or less than the degradation temperature of the underlying patterned material. Other suitable semiconductor materials that can be used in thin film solar cells can also be used, including but not limited to microcrystalline ^ nanocrystalline crystals, hoofed records, and copper ingots. A buffer layer (e.g., doped oxidized) (not shown) may be selectively disposed between the first conductive material 264 and the semiconductor layer 262. The thickness of the buffer layer can be configured to be sufficiently thin to contact the metal plasmonic effect and cause stresses associated with the film but thick enough to adequately block the holes (e.g., about 3 〇 nm to l 〇〇 nm). This buffer layer assists in the collection of electrons and prevents atoms from diffusing between 264 and 262. Other grading or buffer layers can be added to the p-i_n junction to improve its performance. The vane includes an a-Si window layer and a pc-Si (or nc-Si) doped layer. A second conductive material 260 may be disposed on the semiconductor layer 262. When the second conductive material is closest to the light source, the second conductive material may be a transparent oxide layer (TCO layer) of 201208103. The second conductive material 260 may be deposited by evaporation, CVD, sputtering, or the like. Typically, the second electrically conductive material 260 can be deposited at a sample temperature that is lower than the degradation temperature of the underlying layer. The second conductive material 260 may be formed of materials including, but not limited to, indium tin oxide, zinc oxide, tin dioxide, and the like. The flexible conductive layer and, or a combination of materials, can be used with thin film solar cells, including graphite based conductive layers and/or fine metal grids. In general, acceptable materials for conductive material 260 include materials having a high electrical conductivity and a balance of transmittance to sunlight. The second electrically conductive material 260 typically contains a low sheet resistivity, such as about 100 〇hm/sq or less. The thickness of the second conductive material 260 may range from about 5 〇 11111 to 25 〇 11111. The semiconductor layer 262 forms an electrode when the second conductive material 260 is deposited. The array of pyramidal nanostructures can be designed to provide a high aspect ratio to increase the absorptive capacity of the semiconductor layer 162 while maintaining the deposited thickness. The aspect ratio can be between 1 and 10 or more. In one example, the height of the nanostructure 25 Å may range between about 500 nm and 800 nm or more. In another example, the pitch may be between about 500 nm and 1.5 μm or more, and the nanostructure 250 has a width of 25 nm or 300 nm or more. Fig. 16 is a view showing a modification of the nanostructure solar cell 200 shown in Fig. 15, which is shown as a nanostructure solar cell 28A. Nanostructure Solar cell 280 is a reverse design of a nanostructured solar cell 2 , designed to convert light from a source initially on the opposite side of the substrate. Substrate 272 having patterned layer 276 formed thereon includes a patterned pyramidal nanostructure 280 and a residual layer 248. Alternatively the patterned layer itself can be transferred to a substrate using typical etching or other patterning techniques. 27 201208103 The patterned layer 276 can be formed using a polymerizable material (also known as an embossed photoresist) using the lithography technique as previously described to produce a shaped pattern having a thin residual layer therein. The pattern is between the textures. The ruthenium retention layer (10) may have a thickness of less than 5 〇ηηι or less than 25 nm. A minimal residual layer can reduce overall material consumption costs while providing production day (four) silk benefits, as well as reducing light absorption and increasing conversion efficiency. Substrate 272 may be formed from a transparent material comprising glass and/or a clear polymer. Patterned layer 276 can be a transparent polymer. In some cases, it may be preferred to use a conjugated polymer as the embossed photoresist. Once cured, the patterned layer can be oxygen treated to form a glass-like upper surface layer. This upper surface layer itself can advantageously serve as an interface for further deposition of the thin film solar cell b component. It also adds strength and stability to the resulting pattern, while providing greater stability under deposition conditions and lower gas output (which can be pre-baked or oxidized). In addition, it provides a pair of helium water seals to protect the a-Si from environmental degradation. This glazing of the upper surface layer is more advantageous when creating a working template for imprinting the added pattern. A first conductive material 290 is deposited over the patterned layer 276 and can be a transparent conductive oxide (tco) layer. The semiconductor layer 292 is deposited on the first conductive material, and may also be a three-layer (p-i-n) a_si: a_si p layer 292, an a-Si intrinsic layer 293, a-Si η layer 295. In this example, the 1 Å layer can be formed closest to the patterned layer 276 and the predetermined direction of the light source, while the 丨 layer 293 and the 11 layer 295 are subsequently formed. A second conductive material 294 is formed on the semiconductor layer 292 and may be formed of materials including, but not limited to, non-rusting silver 28 201208103 or aluminum, and/or a coated glass or a plastic polymer (eg, PET, PEN) or metal of inorganic materials such as clay and ceramics or other conductive materials having reflective properties, and the like. A buffer layer (i.e., ZnO) can be deposited between 292 and 294 to improve performance. As previously described, the resulting patterned layer and/or nanostructures can be more manipulated to increase surface roughness to provide more light scattering and trapping, with good PCE changes. Figures 24 to 25 show a-Si:Hp-i-n solar cells having a pyramidal nanostructure having a roughened surface. The basic configuration of the solar cell 200a of Fig. 25 is similar to the solar cell 200 of Fig. 15. The embossed layer 212 is formed on the substrate 214 and the ruthenium is subjected to a roughening treatment as described to provide the roughened surface 281a to the pyramidal nanostructure 280a. The metal layer 264a, the ZnO buffer layer 262a, a-Si: a germanium layer (n-i-p layer from the bottom) 266a and a TCO top electrode layer 260a are coated on the substrate to form the solar cell 200a. Similarly, Fig. 24 shows a solar cell 270a similar to the solar cell 270 of Fig. 14. The embossed layer 276a is formed on the substrate 272a and likewise receives a roughening process as described above to provide the roughened surface 251a to the pyramidal nanostructure 250a. The TCO layer 290a, a-Si: a germanium layer (p-i-n layer from the bottom, etc.) 296a, a ZnO buffer layer 292, and a metal electrode 264a are coated on the substrate to form a solar cell 270a. A nanostructure solar cell having a pyramidal nanostructure can be fabricated by the process 1100 shown in the flow charts of Figs. The process of Figure 17 illustrates a process for forming an embossing template for imprinting an array of pyramidal nanostructures in a desired substrate. In the first step 11〇2, a nanoimprinting patterning process is used to form a polymer layer consisting of a grid or a column array on the Shixi wafer. The grid or array of columns will undergo an anisotropic wet etch (e.g., KOH) to form an inverted array of pyramidal nanostructures in the crucible (step 1104). At step 1106, the inverted array is used to reverse emboss a patterned layer of a pyramidal nanostructure on a glass substrate, which is then RIE etched into the substrate at step 1108. . These two steps will be repeated at steps 111A and 1112 to reverse emboss the inverted pyramidal nanostructure array in a second glass substrate. At step 1114, the second glass substrate can be selectively subjected to a buffered oxide etch (B〇E). The boe etch will arc the intersection between the surface of the substrate and the inverted pyramidal nanostructure. A second glass substrate having the inverted pyramid array can be used as an imprint template for patterning a functional photoresist material (i.e., a formable material), such that the equiangular pyramid structure is formed in a selected On the substrate, a flexible substrate comprising glass, polymer, metal, etc., which is used in the manufacture of thin film solar cells, "the embossed material will have a pyramidal nanostructure, and the surface of the substrate and the pyramid There is a rounded intersection between the bases. An imprint template having a positive pyramidal nanostructure for embossing an inverted pyramid nanostructure in a functional photoresist can be easily caused by simply omitting steps 1110 and 1112. The flowchart in Fig. 18 shows that the manufacturing method 1140 can form a solar battery as shown in Fig. 15 using a template made in accordance with the method of Fig. 17. At step 1146, a polymeric material, i.e., an embossed photoresist, is deposited on a suitable substrate. In the case of thin film solar cells, such suitable substrates include glass, flexible glass, plastic, and metal substrates. At step 1148, an imprint template as described above can be used to transfer a pyramidal nanojunction 30 201208103 pattern into the material, which pattern can be positive or negative, depending on the imprint The orientation of the template. At step 1152, an adhesive layer such as Ni is formed by sputtering on the patterned polymeric material, and then at step 1154, a reflective electrode material, such as Ag, is sputtered onto the adhesive layer. on. At step 1156, a buffer layer such as ZnO is sputtered onto the electrode layer. At step 1158, PECVD deposition is used to form an n-i-p a-Si layer. At step 1160, a second conductive material, such as a transparent conductive oxide (TCO) layer, is deposited on the n-i-p a-Si layer. It should be understood that the solar cell of Fig. 16 can be fabricated according to the above-described manufacturing method by merely reversing the positioning of the first and second conductive layers and inverting the pECVD process to form a p-i-n a-Si layer. When embossing lithography is used to create a nanostructured solar cell having an embossed pyramidal nanostructure, it may be desirable to have the imprint template designed to compensate for the shrinkage that the ruthenium polymer material will undergo upon curing. 19A to 19C illustrate the effect of the shrinkage in a typical case, and the template 31 includes an inverted inverted pyramidal nanostructure pattern 350 having a tapered surface 352 and the like, and a Zi template which is similar to the surface of the template. The lanthanide is disposed relative to the substrate, and the polymeric material is deposited as a liquid on the riding surface 344. If the template 3 is moved to the base = 312 ', the template will contact the polymeric material 334, which will fill the pyramidal nanometer. The pattern 355 is then cured as shown in Fig. 1S>B and is bonded to the template: as shown in Fig. 19C, to produce a nanostructure pyramid 354 or the like. Not all dimensions of the shrinking code are shown in Fig. 19C, which is a contraction of 21 to 22 in the vertical axis direction, typically 9 to (4), but there is also a cone 354 passing through the pyramid. - The resulting contraction produces a concave curved cone 31 201208103 face 356. In order to achieve a desired pyramidal nanostructure having a desired height B and a relatively flat tapered surface, it may be necessary to cause an imprinted template having an inverted pyramidal nanostructure having a correspondingly large depth Z3. 'And the tapered surface or the side wall corresponds to the concave tapered surface or the like as shown in Figs. 20A to 20C. The template 31, as shown in Fig. 20A, is designed to have an inverted pyramidal nanostructure pattern 356 having a depth & a concave curved surface 354 and the like, and a depth 相对 relative to the template surface 322. When filled, the uncured polymeric material 334 initially has a corresponding size, as shown in Figure 2B. Once cured, the resulting pyramidal nanostructure will have the desired shape, as shown in Figure 20C, while the shrinkage in the z-axis will reduce its height from Z3 to Z!' and the original concave curved cone It will shrink into a relatively flat cone 352. (Example) A nano-pattern solar cell having a pyramidal nanostructure is produced by the above-described method, and is shown in Figures 21 to 23. An imprint template will be formed first, as shown in Figures 21A-21D. A lithographic wafer is first embossed with a polymeric material, i.e., embossed photoresist, and has an embossed grid array 402 having a pitch of 650 nm, as shown in Figure 24A. The pattern is etched using KOH wet etching to etch the pyramidal nanostructures 4〇4 in the stone, with height and pitch dimensions of approximately 350 nm and 650 nm, respectively, as shown in Figure 2ib. The pattern is imprinted in a photoresist on a glass substrate to form a pyramidal structure 406 (FIG. 21C) and then transferred to the glass substrate by reactive ion ray (rie) A pyramidal nanostructure 45 形成 is formed, as shown in Figure 21D. The process will be repeated to create an inverted pattern of the pyramidal nanostructure on a second glass substrate 32 201208103, which will then receive a buffer oxide for about 1 minute to arc the template surface with the The edge of the base of the inverted pyramid of the template. As mentioned previously. The formed template 嗣 will be used to form the solar cell shown in Fig. 23. The solar cell of Fig. 22 was formed using a similar template as described above but having a height of about 180 nm and a pitch of about 530 nm. Fig. 22 shows a solar cell provided with a pyramidal nanostructure 450b or the like having the above dimensions (about 180 nm in height and about 530 nm in pitch), and which is dry-touched in a glass substrate. This corresponds to a patterned surface having about 15% of the surface comprising the isosceles nanostructure. Ni is sputtered onto the patterned surface to form a Ni adhesion layer of about 1 Onm. Ag嗣 is sputtered onto the adhesive layer to form a first reflective conductive layer 464b of about 1 〇〇 nm, and then a ZnO buffer layer of about 40 nm is formed on the Ag conductive layer by ZnO. An a-Si layer 462b is deposited on the buffer layer by PECVD deposition of n-i-p a-Si to form an approximately 19 nmn layer, a 160 nm layer and a 12 nm layer of n-i-p a-Si. A second conductive layer 460b of a transparent conductive oxide (TCO) is formed by sputtering a layer of indium tin oxide (ITO) by overlying the a-Si layer. Figure 23 shows a second solar cell formed as described above, but using an imprint template to form a pyramidal nanostructure 4 64a having a height of about 305 nm and a pitch of about 650 nm, which is equivalent to A patterned surface has about 50% of the surface comprising the isosceles nanostructure. The first Ag conductive layer 464a, the a-Si layer 462a, and the ITO layer 460a are formed on the pattern as described above. The solar cells of Figures 22 and 23 will be compared to flat or planar solar cells (ie, the substrate is not patterned), as well as solar cells containing random tissue. The randomly organized solar cell is caused by the use of randomly organized tin oxide as a TCO material for constructing the solar cell. The dimensions of the solar cells and the remaining aspects (e.g., Ag layer, n-i-p a-Si layer, top TCO layer of indium tin oxide (ITO)) remain fixed. The results are shown in Table 1. Table 1 Battery Voc Jsc (mA/cm2) FF PCE (%) Plane 0.68 6.8 0.60 2.75 Organizational 0.71 8.6 0.60 3.70 Patterning (15%, Figure 13) 0.69 10.5 0.60 4.37 Patterning (50%, Figure 14 0.7 10.85 0.59 4.51 As can be seen, the solar cell of the pyramidal nanopattern shows a dramatic improvement in energy conversion efficiency (PCE) over conventional flat solar cells and randomly organized solar cells. Also, the density of the pyramidal nanostructures is more likely to cause an increase in PCE, since the 50% solar cell (Fig. 23) outperforms the 15% solar cell (Fig. 22). Fig. 4 shows an a_Si:H p-i-n solar cell of the present invention. Its basic configuration is similar to Figure 2. However, the embossed structure (second portion) will be treated to have an added thickness. This rough surface provides increased light scattering and trapping, which in turn changes the good PCE. Fig. 5 shows an a_Si:H n-i-P solar cell of the present invention having a rough surface. Its basic configuration is similar to Figure 3. The rough tissue can be freed and its fine size is substantially smaller than the major pattern fineness. The rough tissue can be fabricated on the stencil. This roughness can therefore be transferred directly from the template to the stamped photoresist. This roughness can be caused by dry etching. When dry etched, under certain conditions 34 201208103, a polymer or other material may be deposited on the samples and form a micro-mask. This micro-mask effect can make the etched surface rough. Figure 6 shows a dry etched glass with a rough surface on a regularly patterned (larger) pyramid structure. 4 Crude sugar can also be caused by film deposition on the template or directly on the patterned surface of the solar cell. Under certain conditions, the deposited 4 film can be granular and therefore rough. Figure 7 is an SEM image without a thick ιτ film deposited on a patterned glass substrate. All of these processes, including the formation of front and back electrodes, j & F embossing to form nanopatterns, a-Si deposition, and organic layer removal (if available), etc., are preferably The rolling process is compatible to reduce manufacturing costs. All of the concepts and designs discussed here can be applied to single a_si solar cells, as well as tandem solar cells. In addition, the concepts and designs discussed herein can be applied to thin film inorganic, thin film organic, thin film hybrid solar cells and the like. Similarly, such designs can be applied to tandem solar cells and the like which comprise a thin film solar cell. In some cases, it can be applied to C-Si. For example, in C-Si, the organized surface reduces frontal reflection. Since the formation of C-Si solar cells continues to be thinned in the industry (e.g., reduced to 20 or 50 gm), the nanopattern with the back reflector can improve PCE. Further modifications and variations of the various aspects will be readily apparent to those skilled in the art. Therefore, the description is to be considered as illustrative only. It should be understood that the forms shown and described are to be considered as examples. The components and materials may be replaced for those shown and described, the parts and processes may be reversed, and certain features may be utilized independently, all of which may be in the interest of 35 201208103. It is easy to know later. The changes can be made in the described elements without departing from the spirit and scope as set forth in the appended claims. I: Schematic description of the drawing 3 Fig. 1 shows a simplified side view of an exemplary imprint lithography system. Fig. 2A shows a simplified side view of one of the substrates shown in Fig. 1, with a patterned layer having a nanostructure thereon. 2B to 2E illustrate top views of an embodiment of a nanostructure. Figures 3 to 6 show simplified side views of an embodiment of a nanostructure solar cell formed in accordance with the present invention. Figure 7 shows a simplified side view of a patterned layer wet etch to increase the relative height of the nanostructure. 8A-8B illustrate a simplified side view of a patterned layer of a solar cell. 9A to 9C illustrate a simplified side view and a plan view of one of the solar cells as an example of a nanostructure pattern. 10A to 10C illustrate one example of forming a texture fine structure in a conductive layer. Figure 11 shows a simplified side view of one embodiment of a nano-solar cell having a fine texture in a conductive layer. Figure 12 is a simplified perspective view of another embodiment of a nanopattern substrate for use in a thin film solar cell formed in accordance with the present invention. Fig. 13 is a top plan view showing a section of the nano pattern substrate of Fig. 12. 36 201208103 Figure 14A shows a simplified side view of a section of the nanopattern substrate of Figure 12. Fig. 14B is a simplified side elevational view showing one of the sections of the nanopattern substrate of Fig. 14A. Figure 15 is a simplified side elevational view of one embodiment of a nanopatterned thin film solar cell formed in accordance with the present invention. Figure 16 is a simplified side elevational view of another embodiment of a nanopatterned thin film solar cell formed in accordance with the present invention. Fig. 17 is a block diagram showing an exemplary system for forming the nano pattern thin film solar cell of Fig. 15. Fig. 18 is a block diagram showing an exemplary system for forming the nano pattern thin film solar cell of Fig. 16. 19A to 19C illustrate an exemplary template of a nano pattern substrate for forming a thin film solar cell. 20A to 20C illustrate another exemplary template for forming a nano pattern substrate of a thin film solar cell. 21A to 21D illustrate scanning electron micrographs of a nanopattern substrate for forming a nanopattern thin film solar cell shown in Fig. 6. Fig. 22 shows a scanning electron micrograph of a nano-pattern thin film solar cell similar to the solar cell shown in Fig. 6. Fig. 23 shows a scanning electron micrograph of another nanopattern thin film solar cell similar to the solar cell shown in Fig. 6. Figures 24 to 25 show a simplified side view of an embodiment of a nanopattern thin film solar cell having a nanostructure with a roughened surface. 37 201208103 Figures 25 to 26 show scanning electron micrographs of a nanopattern film layer having a nanostructure having a roughened surface. [Main component symbol description] 100,200,270... nanostructure solar cell 110... light lithography system 112.212.214.272.274.312.. substrate 114.. substrate chuck 116...step 118 .. . Imprint template 120.. . boss 122.. patterned surface 124... recess 126.. convex 128.. template chuck 130.. embossing head 132.. . Fluid dispensing system 134.. . Formable material 138.. Energy 140.. Energy 142.. Path 144, 344... Substrate surface 146, 276... Patterned layer 147.. Step pattern 148, 248.. Residual layer 149.. small area 150, 152... nanostructure 151.. extension 153·. column 154.. processor 155.. straight line 156.. memory 157.. box Pattern 160, 260a... transparent conductive oxide (TCO) layer 161, 261, 292... a-sip layer 162.. active layer 163, 263, 293... a-si intrinsic layer 164.. Back reflection layer 164b, 180... conductive layer 165, 265, 295... a-sin layer 166.. recessed area 167b... contact 38 201208103 168.. top 170.. anti-reflection layer 172, 262a ·.. buffer layer 174.. sidewall 182.. wet etching layer 212a, 276a... embossing layer 250, 280... pyramidal nanostructure 251a , 281a, 551a, 551b... Rough surface 260, 264, 290, 294... Conductive material 262, 292... Semiconductor layer 300, 310... Template 322.. Template surface 334.. Polymer material 350.. . inverted pyramidal nanostructure pattern 352.. · cone surface 354.. nano structure pyramid 354, 356... concave curved surface 355, 404, 406, 450... pyramidal nanostructure 402.. Array 460, 464... Conductive layer 462.. . a-si layer 550a, 550b... nanostructure 1100, 1140... method 1102, 1114, 1146~1160... process steps 39 201208103 invention Patent Description f (Do not change the format and order of this manual, please do not fill in the ※ part) ※Application number: (Yangsuke 蛑p ※Application 曰: (ρ·^, ι / ※) (: Category: First, the name of the invention: (Chinese / English)

Nanostructured solar cell NANOSTRUCTURED SOLAR CELL II. Abstract of the invention: ^ A system and method for fabricating a nanostructured solar cell having a nanostructure array, including a nanocrystal having a repeating pyramidal nanostructure pattern Structured solar cells' offer low-cost thin-film solar cells with improved PCE. Third, the English invention summary:

H〇\L -2006.01 , 2006,01 W\o\L

Systems and methods for fabrication of nanostructured solar cells having arrays of nanostructures are described, including nanostructured solar cells having a repeating pattern of pyramid nanostructures, providing for low cost thin film solar cells with improved PCE. 1 201208103 VII. Patent application scope: ^ — The solar cell comprises: a substrate having an array of polymerized nanostructures extending therefrom; a conductive material disposed on the substrate; a semiconductor layer disposed on the first conductive material; and a second A conductive material is disposed on the semiconductor layer. 2. The solar cell of claim 1, wherein the nanostructures have a shape selected from the group consisting of: a line, a column, a hole, a pyramid or a peculiar shape. ^3' The solar cell of claim 1 or 2, wherein the nanostructures have a height between 1 〇〇 nm and 2 μπ1, a width between 1 〇〇 nm and 2 cm, and A spacing between 5 〇〇 nm and 2 μιη. 4. If you apply for a patent scope! A solar cell according to any one of the items 3 to 3, wherein the side nanostructure has an aspect ratio of 0.5 to 10. 5. The solar cell of claim 1 to 4, wherein the nanostructures have a roughened surface. 6. The solar cell of claim 1 to 5, wherein the substrate is electrically conductive. The solar cell of claim 1 to 6, wherein the first conductive material is reflective and the second conductive material is transparent. A solar cell according to any one of claims 1 to 6, wherein the substrate and the first conductive material are transparent, and the second conductive material is reflective. 9. The solar cell of claim 1 to 8 wherein the semiconductor 40

Claims (1)

201208103 » A grainy thin layer of tantalum is deposited on the mysteriously patterned nanostructure. 18. The method of any one of clauses 1-5 to wherein the patterned layer is formed to have a residual layer and further comprising removing the residual layer. The method of claim 18, wherein the residual layer is removed by etching with νυν. The method of any one of claims π to 19, wherein the patterned layer is transferred to the substrate by wet etching. 21. The method of claim 20, wherein the wet etching increases the fineness and aspect ratio of the nanostructure. 22. The method of any one of claims 1-6, wherein the patterned layer enhances the plasmonic effect to increase light trapping. 23. The method of any one of clauses 11 to 22, wherein the substrate provided is flexible. 24. A solar cell comprising: a substrate having a surface and having a repeating pyramidal nanostructure pattern extending from the surface and at the intersection between the surface and the beauty of the isosceles nanostructure Optionally, the arc is: the first conductive material is disposed on the substrate; a semiconductor layer is disposed on the first conductive material; and a second conductive material is disposed on the semiconductor layer. 25. The solar cell of claim 24, wherein the equiangular pyramid structure has a height between 1 ΟΟηηι and 2μηι, and - a spacing between 300 nm and 2 μηη. The solar cell of claim 24, wherein the angle between the surface and the tapered surface of the isosceles structure is between 110 and 150 degrees. 27. The solar cell of any one of claims 24 to 26, wherein the base between the equilateral pyramidal structures is between 0 and 500 nm. 28. The solar cell of any one of claims 24 to 27, wherein the isosceles nanostructure is formed by imprint lithography. 29. The solar cell of any one of claims 24 to 28, wherein the substrate is flexible. The solar cell of any one of claims 24 to 29, wherein the first conductive material is reflective and the second conductive material is transparent. The solar cell of any one of claims 24 to 29, wherein the substrate and the first conductive material are transparent, and the second conductive material is reflective. The solar cell according to any one of claims 24 to 31, wherein the semiconductor layer is selected from the group consisting of amorphous ruthenium, microcrystalline ruthenium, nanocrystalline crystallization, crystallization, and copper. Indium gallium telluride. 33. A method of making a solar cell, comprising: providing a substrate having a surface and having a repeating pyramidal nanostructure pattern extending from the surface and between the surface and a base of the isosceles nanostructure The intersection is arcuate; depositing a first conductive material on the patterned substrate; depositing a semiconductor material on the first conductive material; and 43 201208103 depositing a second conductive material on the semiconductor material. 34. The method of claim 33, wherein the substrate providing step further comprises: forming a polymer layer on the surface of the substrate, the polymer layer comprising the pyramidal nanostructure. 35. The method of claim 34, wherein the equiangular nanostructures have a residual layer of less than 25 nm between them. The method of claim 34, wherein the polymer layer contains ruthenium and further comprises a surface oxidizing the ruthenium-containing polymer layer. 37. A method of forming an imprint template, comprising: stamping a wafer with a repeating grid or column array; wet etching the wafer to form a repeating inverted pyramid pattern; using the patterning The Shishi wafer is stamped with a first glass substrate, and a repeating pyramid pattern is formed on the glass substrate; the repeated pyramid pattern is transferred to the glass substrate; the imprinting and transferring steps are selectively repeated Forming an inverted repeating pyramid pattern on a second glass substrate; and etching the glass substrate with the buffered oxide to cause a bond between the surface of the substrate and the base of the isometric tapered nanostructure Arced intersection. 38. A template for imprinting a polymeric material, an array of pyramidal nanostructures extending from the surface of the material and being rounded at the intersection between the surface and the base of the isosceles nanostructure Arcing, wherein the template comprises an embossed surface comprising an inverted inverted pyramid 44 201208103 column having dimensions different from the desired embossed array to compensate for curing of the polymeric material Contraction. 39. The template of claim 38, wherein the inverted-corner nanostructure of the template has a depth greater than a desired height of the embossed pyramidal nanostructure, and the inverted-angle pyramid of the template The tapered surface of the rice structure is concave. 40. A method of replicating a template for imprinting a polymeric material, the array of repeating patterns having a pyramidal nanostructure extending from the surface of the material and between the surface and the base of the isosceles nanostructure The intersection is rounded, and the method comprises the steps of: imprinting a stone wafer with a repeating grid or column array; wetly engraving the stone wafer to form a repeating inverted pyramid pattern; The patterned germanium wafer is imprinted with a polymeric material deposited on a glass substrate to form a repeating pyramid pattern on the glass substrate; the repeated pyramidal pattern is transferred by dry etching the substrate To the glass substrate; and etching the glass substrate with the buffered oxide to create the arcuate intersection between the surface of the substrate and the base of the isosceles nanostructure to form a main a template; the second template is used to imprint the polymer material deposited on the added glass substrate to form a repeated inverted pyramid pattern on the added glass substrate; transferring the repeated inverted pyramid pattern to The Glass substrate to form a working handle plate. 45 201208103 7 /f ο 1y 48 Figure 2A 201208103 mi 广150 / /-150a /-150b 〆 Brother 2B Figure 2C Figure 2E Figure 2D