TW201246560A - A method for forming a bifacial thin film photovoltaic cell and a thin film solar device - Google Patents

Abstract

A method for forming a bifacial thin film photovoltaic cell includes providing a glass substrate having a surface region covered by an intermediate layer and forming a thin film photovoltaic cell on the surface region. Additionally, the thin film photovoltaic cell includes an anode overlying the intermediate layer, an absorber over the anode, and a window layer and cathode over the absorber mediated by a buffer layer. The anode comprises an aluminum doped zinc oxide (AZO) layer forming a first interface with the intermediate layer and a second interface with the absorber. The AZO layer is configured to induce Fermi level pinning at the first interface and a strain field from the first interface to the second interface.

Description

201246560 ... 6. Description of the Invention: [Technical Field of the Invention] [0001] The present invention generally relates to a photovoltaic device and a manufacturing method. More specifically, the present invention provides a method and apparatus structure for a double-sided thin film photovoltaic cell. Embodiments of the present invention include a method for forming a double-sided film photovoltaic device that utilizes Fermi level pinning and strain fields in the anode to change the internal electric field to improve cell efficiency. One application of the invention is to use a strained AZO layer as the interface between the PV absorber and the anode layer for enhanced hole collection.

D [Prior Art] [0002] Humans have tried to find ways to use energy from the very beginning. Energy is presented in the form of petrochemicals, hydroelectric power, nuclear, wind, biomass, solar energy, and such as wood and coal. In the last century, modern civilization has relied on petrochemical energy as an important source of energy. Petrochemical energy includes natural gas and petroleum. This includes the lighter U-types such as Ding and Chong, which are commonly used to heat homes and for use as fuel for cooking, as well as gasoline, diesel, and jet fuels commonly used for transportation purposes. The heavier form of petrochemistry can also be used to heat the home in some places. Unfortunately, the supply of petrochemical fuels is limited and the supply is essentially fixed based on the amount available on Earth. In addition, as people use more and more petroleum products, they quickly become scarce resources. [0003] Environmentally clean and renewable energy sources are desirable. An example of clean energy is hydroelectric power. Hydroelectric power is derived from generators driven by water flow generated by dams. Clean and renewable energy sources include wind, wave, 10110861# single number should be 01 page 3 / total 28 pages 1013265466-0 201246560 biomass and so on. Windmills convert wind energy into more useful forms of energy, such as electricity. Other forms of clean energy include solar energy. [0004] Solar technology generally converts electromagnetic radiation from the sun into other useful forms of energy. These other forms of energy include heat and electricity. For power applications, solar cells are often used. Although solar energy is environmentally clean and has been successful to a certain extent, there are many limitations that need to be addressed before it is widely used throughout the world. As an example, one type of solar cell uses a crystalline material derived from an ingot of a semiconductor material. These crystalline materials can be used to fabricate photovoltaic devices that include photovoltaic and photodiode devices that convert electromagnetic radiation into electrical power. However, crystalline materials are generally expensive and difficult to manufacture on a large scale. Other types of solar cells use "film" techniques to form a film of photosensitive material for converting electromagnetic radiation into electricity. There are similar limitations to the use of thin film technology in the manufacture of solar cells. That is, efficiency is usually low. In addition, membrane reliability is generally low and cannot be used for long periods of time in traditional environmental applications. Generally, it is difficult for the films to be integrally formed with each other by mechanical means. These and other limitations of these conventional techniques can be found throughout the specification and will be described in more detail below. [0005] As an effort to improve the efficiency of thin film solar cells, the process for improving the relative band alignment at the heterojunction of the cell plays an important role in improving the final performance of the solar cell. There are a number of manufacturing challenges in selecting materials and structures for forming a thin film PV cell junction interface with suitable electric field strength and orientation. Specifically, the collection rate of the carrier between the absorber and the anode or between the window layer and the cathode through the corresponding interface is 10110861^^ A〇101 4th/28 pages 1013265466-0 201246560 As well as the traditional techniques of electric mines, some of the tongue-and-shoot questions have been solved, but in the famous case, the traditional technology street is usually insufficient. Accordingly, it is desirable and advantageous to have a method and structure for designing a battery junction interface for a photovoltaic device. [Invention] [0006] The present invention provides a method for forming a double-sided thin film photovoltaic cell. The method includes providing a glass substrate having a surface region covered by an intermediate layer, and forming a coated photovoltaic cell on the surface region. The thin film photovoltaic cell includes an absorber overlying the anode of the intermediate layer located above the anode. In addition, the battery includes a window layer and a cathode above the absorber, and a buffer layer between the window layer and the cathode. The anode includes an aluminum doped zinc oxide (germanium) layer for forming a first interface with the intermediate layer and a second interface with the absorber. The ΑΖΟ is constructed such that the bow picks up the Fermi level at the first interface and the strain from the first interface to the first interface; [0007] In an alternative embodiment of the invention, a thin solar device utilizing a strained ruthenium layer for the anode absorber interface is provided. The device comprises an optically transparent substrate and an intermediate layer 9 covering the transparent substrate. Further, the device comprises an anode layer comprising an aluminum-doped zinc oxide (ΑΖΟ) layer to form a first interface with the intermediate layer. The apparatus also includes an absorber comprising a copper indium gallium diselenide having a bismuth-type dopant to form a second interface with the ΑΖ0 layer. In addition, the device includes a buffer layer followed by a window layer covering the absorber. In addition, the device includes a cathode that covers the window layer. In a specific embodiment, the ruthenium layer utilized by the 9-thin device causes a strain field in the anode layer and a Fermi level nail at the first* interface. 10110861#单号Α_第5页/共28贡1013265466-0 201246560 Tie to change the internal electric field at the second interface. Some embodiments of the present invention provide a method of utilizing a combination of strain in an anode and Fermi level pinning at an interface to change an internal electric field around an anode-absorber interface to reduce electric field strength or even Flip the direction of the internal electric field. The reduced internal electric field strength causes the barrier to drop to more easily tunnel from the absorber through the absorber to the anode. The direction of inversion of the internal electric field at the interface between the absorber and the back electrode directly assists in the accumulation of holes from the P-type absorber through the n+ type anode. [0009] The intermediate layer is disposed between the AZO layer and a surface region of the substrate. A lattice mismatch between the AZO layer and the intermediate layer causes strain in the anode which changes the electric field at the interface between the anode and the absorber. At the interface between the AZO layer and the intermediate layer or between the AZO layer and the absorber, the electronic tape is changed by the surface state and aligned across the interface by the Fermi level pinning. Both the Fermi level pinning and the strain in the anode enable the internal electric field to be reduced or even flipped at the back electrode, which aids in the accumulation of holes at the back contact and thereby increases cell efficiency. [Embodiment] [0010] Embodiments of the present invention provide a method and apparatus for a double-sided thin film photovoltaic cell. Embodiments of the present invention include methods for forming a double-sided thin film photovoltaic device using strain fields and interface Fermi level in an anode layer to alter the internal electric field at the anode absorber interface to improve cell efficiency. A device is provided for using an AZO layer as an interface between a PV absorber and an anode layer to enhance hole collection. [0011] FIG. 1 illustrates an anode absorber interface in accordance with an embodiment of the present invention. 1013265466-0 Page 6 of 28 201246560 A diagram of a thin film photovoltaic cell with an aluminum doped zinc oxide layer. As shown, a thin film photovoltaic (PV) cell is formed on the substrate 101. Generally, for a double-sided thin film PV cell, a transparent material such as nano-glass is selected for the substrate. In the embodiment, the intermediate layer 105 is formed to cover the surface area of the substrate 1〇1. The intermediate layer 105 is a base layer for a back electrode (typically an anode). In a specific embodiment, the intermediate layer 105 can act as a barrier to prevent sodium elements from diffusing from the nano-calcium glass into the electrode layer. [0012] 另一 In another embodiment, 'intermediate layer 1〇5 is optically transparent to sunlight' to facilitate absorption from the back side of the cell>> intermediate layer 1〇5 is preferably a transparent oxide layer, The oxide layer is made of a material selected from the group consisting of fluorine-doped tin antimonide (TFO), indium tin oxide & (ITO)', and bismuth or nitride. In another embodiment, if a conductive material is selected, the intermediate layer 105 can be part of the back electrode of the battery 1' and the intermediate layer is configured to form an electrical contact for the battery anode. For example, a thin film of transparent conductive oxide and/or metal ο (such as molybdenum) may be contained in the intermediate layer 1G5. Further, a strain field in a layer covering its own growth is controlled by allowing an intermediate layer 1 〇 5 of the interface to be used as a structural base layer side to provide a lattice of the constant. The layer formed on the top thereof can be protected in a controlled manner under strain based on lattice mismatch. As shown in FIG. 1, the anode layer 110 is formed to cover the intermediate layer 1〇5. In the embodiment, the anode layer 110 is an aluminum-doped zinc oxide. In a specific (AZO) layer * single number 10110861^, at least a first interface 107 is formed between the AZO layer 11 and the intermediate layer 105. The film of aluminum-doped zinc oxide is transparent and is electrically conductive. The optical properties of AZO are characterized by high transmittance in the visible region and A0101 page 7/28 pages 1013265466-0 201246560 and ~12 /zm It has a useful transmittance for long IR wavelengths. The AZ0 layer 110 can be deposited by sputtering from a target composed of 2-4% of A1 metal (or in the form of A1203) incorporated in ZnO. The AZ0 layer 110 can be integrated by RF or DC magnetrons, wherein the target energy density is about 3 W/cm2 or less in a vacuum chamber having a pressure range of about 1-1 〇 mtorr (mTorr), and oxygen and argon are mixed. The gas flows in the vacuum chamber. Alternatively, the ΑΖ0 layer can be formed by a method using M0CVD. After 20 layers are formed on the intermediate layer 1〇5, aluminum serving as an η-type dopant can have an atomic level varying from 5x1019 cm-3 to lxl〇21 cm-3 in the anode. Conductivity (which is measured as volume resistivity or as sheet resistance) is related to deposition characteristics and layer thickness. [00M] Referring to FIG. 1, the absorber 115 is formed to cover the AZ0 layer 11D such that between the anode 110 and the absorber 115 At least a second interface 112 is formed. The absorber 115 of the battery is of a photovoltaic material, typically a p-type semiconductor film. In a particular embodiment, the absorber 115 is opened by heat treating the precursor layer in a gaseous environment. For example, a precursor layer including a copper element, an indium element, and/or a gallium element may be formed on the surface of the substrate by sputtering. In the subsequent reaction heat treatment, the precursor layer can be reactively treated in a gaseous environment in a furnace tube containing a sample substance, a sulfur substance, and a nitrogen substance. When the furnace tube is heated, gaseous ruthenium interacts with the copper-indium-gallium species in the precursor layer. Due to the reactive heat treatment, the precursor layer is converted into a photovoltaic film stack comprising a copper indium (gallium) diselenide (CIS/CIGS) compound. The photovoltaic film stack is a p-type semiconductor and is used as an absorber for forming photovoltaic cells. Layer. [0015] Regarding the heat of the CIGS photovoltaic film laminate for forming a thin film solar cell 10110861# single number A 〇 101 帛 8 pages / total 28 pages 1013265466-0 201246560 More detailed description of the process can be in May 2009 14th by Robert

Wieting submitted the name "Method and System for

Selenization in Fabricating CIGS/CIS Solar

The US Patent Application No. 61/178,459, which is commonly assigned to the St. Joseph City, is found in the United States Patent Application No. 61/178,459, which is incorporated herein by reference.

Corporation' and the U.S. Patent is hereby incorporated by reference. In some embodiments, the absorber 115 can be made of a cadmium telluride compound semiconductor having a p-type dopant Ο. Of course, there can be other variations, modifications, and alternatives. For example, where the absorber is shown as a single junction structure 'but the absorber may alternatively be formed in a battery having two or more junctions or variably repeated in a battery having two or more junctions 〇[0016] 上方 Above the absorber 11 5, the battery 1 includes a window layer 125. In a specific embodiment, a buffer layer 120 can be inserted between the window layer 125 and the absorber 115. The electrical characteristics of the buffer layer 120 are n-type, and the electrical characteristics of the window layer 125 are η η + type. In one embodiment, the buffer layer 12 can be made from a cadmium sulfide compound using a chemical bath deposition (CBD) process. In another embodiment, the buffer layer can be made of zinc oxide using a MOCVD process. Instead of the sputtering method, the M0CVD method is used to form the zinc oxide buffer layer, so that possible structural damage to the second interface caused by the sputtering technique can be greatly reduced. In a preferred embodiment, the window layer 125 is a ΑΖ0 layer having a thinner thickness than the absorber 115. In certain embodiments, the window layer 125 can be used to form a cathode contact for a solar cell. Alternatively, an additional layer of 1010861# single number Α0101, page 9 / 28 pages 1013265466-0 201246560, made of boron doped oxide, may be added by the MOCVD method to form a front end electrical contact having n+ electrical characteristics. [0017] In order to construct a thin film solar cell, a double-sided battery structure has been used with the aim of enhancing photon absorption from both sides of the absorber. Figure 2 is a simplified diagram showing the internal electric field across the interface of the absorber and its typical double-sided structure. In this structure, both the anode and cathode layers are made of AZ0 material having η + electrical characteristics, and a P-type absorber is sandwiched therebetween. Because of the structural configuration and electrical properties under equilibrium conditions, the internal electric field at both interfaces of the absorber can have a direction from the electrical contact to the absorber. As shown in Fig. 2, specifically, the electric field E3 is directed to the p-type absorber at the rear contact point. This configuration is not conductive to the accumulation of holes. In other words, the signal of E3 is transmitted against the hole from the absorber to the back contact. In terms of energy, the strength of the internal electric field is associated with a strong energy barrier so that holes pass through. [0018] FIG. 3A is a simplified diagram showing a heterojunction strip structure of a double-sided battery. It shows a valence band EV and a conduction band Ec of a typical double-sided battery structure in which n + transparent oxide is used as a rear contact, the anode contact is on the left side and the cathode is on the right side. Figure 3B is a close up view of the ribbon structure at the anode absorber interface of the double sided battery. As shown, the barrier is present at the anode-absorber interface such that the cell must rely on tunneling current to concentrate carrier holes through the back contact. The holes typically do not have sufficient energy for emitting thermions. Here, the electric field is directed to the absorber to oppose the tunneling of the holes. Without the accumulation of effective carrier holes, solar cells cannot produce a sufficiently high PV current as a basis for solar cells with high efficiency. Therefore, it is desirable to use a mechanism to reduce the tunneling barrier or even change the signal of the internal electric field at the anode-absorber interface by changing the internal electric field in the anode to account for the tunneling current. Single Number A_ Page 10 / Total 28 Page 1013265466-0 201246560 [0020] Ο The present invention provides a method of changing an internal electric field using a rear electrode structure, the back electrode structure comprising a ΑΖ0 material, the material covering being first arranged An intermediate layer on the surface area of the (transparent) substrate. The method includes utilizing lattice mismatch strain to vary the internal electric field across the anode-absorber interface. Figure 4 is a strained film showing an interface comprising two materials with mismatched lattice spacing. As shown in the figure, when two materials Α and 具有 having different lattice spacings in respective natural states are arranged together, such as by arranging the Β material layer in the enamel material layer, the two layers are matched. In order to achieve an equilibrium thermodynamic state in which the free energy of the Α+Β system is reduced, the material Β has a lattice constant αΐ, and the lattice constant ^^ is larger than the lattice constant α〇 of the material Α. The material Β will be under compressive stress to accommodate the small lattice of the material while the latter will be under tensile stress. At each of the layers (where - one is in compression and one in tension), the strain can be directly related to the value of (αΐ - αΟ) / α0. The thin-lying properties under stress are changed with respect to the state of self-involvement, energy band alignment, sub-mobility, recombination rate of minority carriers, shape, degree, _ field, etc. due to assisted strain By appropriately constructing the interface structure, the above-mentioned alternation of physical properties can be controlled according to the interface structure. # 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为 为In other words, according to an embodiment of the present invention, the "sub-aggregation enthalpy of a thin film-based solar cell can be improved by using strain in the anode" to reduce a tunneling barrier for collecting holes from the absorber. As shown, the energy barrier that is broken by the conduction band offset (with the order of the bp-offset) exists between the nucleus and the Wei apparatus. The desired page 11 / total 28 true 1 〇 1 surface 1 production order number A0101 1013265466- 0 201246560 The band offset can range from 0.1 eV to 0.3 eV. The relative band alignment between the various materials in the battery determines the properties of the IV curve and thus the battery efficiency factor. (especially in the conduction band Those discontinuities) cause irregularities or "kneading" in the IV curve of the battery. The relative band alignment at the heterojunction in a thin film-based solar cell is a major factor in determining the final performance. The field is reasonable for the separation of electrons and holes in the space charge region. The carriers generated in the quasi-neutral region diffuse to the edge of the space charge region where the carriers drift under the influence of the internal electric field. When the strain in the anode layer is changed and thus the internal electric field is changed, the band alignment at the interface can be adjusted to facilitate the accumulation of carrier holes. For example, the internal electric field can be reduced, thereby enabling The energy barrier for hole tunneling can be greatly reduced. Alternatively, the internal electric field is flipped in the opposite direction towards the anode, directly assisting the carrier flow. [0021] Selection of materials and structures that affect the anode-absorber interface Another effect includes the phenomenon of Fermi level pinning at the interface. The pinned surface can lower the diode (diode) and thus reduce the photovoltaic response of the battery. The performance of a variable cell. Most semiconductors have dangling bonds with breaks at chemically active surfaces. Asymmetric cleavage in the potential energy of the crystals results in the formation of an energy state of the intermediate void defect that acts as a recombination center. These surface states may Is a determining factor in the position of the Fermi level (instead of the intrinsic carrier class). The range of Fermi level pinning is determined by the density of the surface states, the cross sections they acquire and their position in the energy band. It is determined that during the sequential formation of the film laminate, since the upper layer covers the lower layer, the surface state is substantially maintained at the interface. View _#单编号 A0101 Page 12 / Total 28 Page 1013265466-0 201246560 Fee for interface state The pinning of the meter level causes the space charge region across the interface to be "cold; east" 'ie' which predetermines the alignment and bending of the strip from the absorber to the anode, regardless of the doping level across either layer of the interface. [0022] FIG. 5 is a graph of a modified internal electric field through a combination of strain in an anode and interface Fermi level pinning at an anode-absorber interface, in accordance with an embodiment of the present invention. As shown, the intermediate layer 105 is disposed on the substrate 1〇1 before the anode layer 11 is formed (and then the absorber layer 115 is formed). In some embodiments, the intermediate layer 1〇5 serves at least two functions for improving the thin film-based double-sided solar cell by changing the internal electric field therein. The intermediate layer forms a first interface 107 between the n+ semiconductor AZO layer 110 and the intermediate layer 1A5. At the first interface, the broken chemical bonds of any of the two layers and the reconstitution of the interface atoms result in an interface state which directly leads to the Fermi level pinning effect. In addition, the Fermi level pinning 108 at the first interface 1〇7 is coupled to the Fermi level pinning 111 at the second interface 112, which is located between the AZO layer 110 and the absorber 115 formed thereafter. . Since the Fermi level pinning at the interface is 1〇8 and 111, the energy barrier for hole tunneling can be adjusted to improve the carrier aggregation efficiency while reducing the electron-hole caused by light. Combine again. [0023] Next, the intermediate layer 105 formed over the glass substrate 101 sets a base layer for forming the AZO layer 110, which can be utilized to better control the subsequent placement of the AZO layer directly over the glass substrate 101. Lattice mismatch strain in the formed AZO layer 110. In one embodiment, the material and thickness of the intermediate layer 105 is used as an engineering parameter to adjust the strain field within the AZO layer 110. For example, the intermediate layer may include a material having an (average) lattice constant (the lattice constant is smaller than the lattice constant of the AZO layer), A single nickname 10110861$ A0101 page 13 / total 28 pages 1013265466-0 201246560 to The overlay AZQ layer is controlled to be in a compressed state. The intermediate layer may include a material having a larger lattice constant such that the strain field covering the ΑΖ0 layer can be converted into tensile properties. The AZO layer can be formed by using a sputtering technique doped with a word or a dry oxide. Alternatively, the ΑΖ0 layer can be formed by the MOCVD method. The AZ layer 11〇 may include heavily doped human quinone species varying from 5χΐ〇19 d3 to 1J 1x1021 cm_3. [0024] FIG. 6 is a SEM image of a cross-sectional surface of a sputtered AZO layer having an oriented cylindrical state, which is characterized by a zinc oxide film formed by sputtering, characterized in that the cylindrical opening is eight t, and the orientation of the cylindrical structure is substantially The ground is perpendicular to the substrate and penetrates the entire film thickness of about 6〇〇11111. In terms of atomic structure, zinc oxide (ZnO) or zinc oxide doped with Is (ZnG: A1) is a wurtzite structure (see the inset in Fig. 7), which has a unit cell, and the unit cell has 1)) The elongated c_ axis perpendicular to the zinc atomic layer and the oxygen atomic layer in the plane. Figure 7 also shows an X-ray diffraction pattern with a dominant [002] apex, which clearly refers to the orientation of the non-circular shape along the c-axis. For the ZnO or AZ layer 11 形成 formed on the intermediate layer 1 〇 5, the c_ axis is perpendicular to the first interface 107. The oriented zinc telluride film exhibits the greatest piezoelectric effect which is an advantageous property that can be used to control strain-induced changes in the internal electric field in the film. The inset of Figure 7 also shows the unit cells of zinc oxide under pressure, one in a compressed state and one in a stretched state. As shown, the unit cell contracts or expands only in the U0G plane, and accordingly extends or contracts along the axis of the pad due to the c-axis being perpendicular to the interface 1〇7. Thus the mismatch strain in the 211 〇 or tier is directly realigned in the cell with its atomic distance and changes its intrinsic piezoelectric properties, which then causes the internal electric field in the AZ 〇 layer to alternate and pass page 14 / A total of 28 pages 10110861# single number ΑΟίοι 1013265466-0 201246560 The second interface reaches the upper film such as the absorber layer covering the ΑΖ0 layer. [0025] Referring to FIG. 5, in a particular embodiment, strain in the anode 110 (caused by lattice mismatch between the anode layer 110 and the underlying intermediate layer 105) is associated with the anode layer 110 and the intermediate layer 105. The combination of Fermi level pinning at the first interface 107 causes the internal electric field to decrease at the second interface 112 between the anode 110 and the absorber 11 5 . In one embodiment, the intensity of the internal electric field E3 across the second interface 107 is reduced by the combined effect of stress and Fermi level pinning. In another embodiment, the internal electric field E2 across the second interface 107 is flipped over to rotate its direction toward the anode rather than to the absorber. These can greatly alter the tunneling barrier so that holes pass from the absorber to the AZ0 layer and/or directly help the hole flow to increase the rate of aggregation of holes by the back electrode contact. As a result of the combined effect, thin film based photovoltaic cells can have greatly improved photon-to-electronic conversion efficiencies that provide efficiency for solar modules. In an alternative embodiment, the internal electric field of the anode layer can be varied by changing the associated Zn and oxygen components near the second interface within the AZ0 layer. For example, when a zinc oxide is formed or a layer of AZ0 is specifically formed, the oxygen content in the sputtering working gas can be reduced or increased so that the ZnO or Ζn: Α1 formed by sputtering can be rich or oxygen-rich. . In the atomic energy level, the Zn atom in the plane of the Zn atom can be replaced by excessive oxygen or other means. This can change the intrinsic strain, piezoelectric properties, interface energy state and Fermi level pinning, and the final internal electric field. [0027] While the invention has been described with respect to the embodiments of the present invention, it is understood that the various methods of the invention may be employed in various embodiments without departing from the spirit and scope of the invention. Change 1011086# Single Number Toilet 01 Page 15 / Total 28 Page 1013265466-0 201246560 , Modifications and variants. For example, the use of a ΑΖ0 layer for the post-contact layer is shown as an example. Other transparent conductive layers can be used to increase photovoltaic conversion efficiency, which can be adjusted in one way or another to change the electric field within the anode-absorber interface and subsequently change carrier aggregation at the post electrical contacts. Due to the nature of double-sided photovoltaic cells, it is important to control the electric field within the interface by one or more materials or structural parameters to increase charge separation and increase the efficiency of carrier aggregation at the front and back electrodes of the cell. Furthermore, although the above embodiments have been applied to absorbers made of CdTe' or CIS and/or CIGS and covered by a ΑΖ0 layer for front and back electrical contact in a film stack, they have a single, two Other film-based double-sided solar cells, or multiple junctions, may also benefit from this embodiment without departing from the invention described in the claims herein. BRIEF DESCRIPTION OF THE DRAWINGS [0028] FIG. 1 is a view showing a thin film photovoltaic cell using an aluminum-doped oxide layer at an anode absorber interface; [0029] FIG. 2 is a cross-over absorber FIG. 3A is a diagram showing a heterojunction energy band structure of a double-sided battery; [0031] FIG. 3B is an anode-absorber of a double-sided battery a closer view of the energy band structure at the interface; [0032] FIG. 4 is a diagram showing a strained film comprising an interface of two materials having a mismatched lattice spacing; [0033] FIG. 5 is a diagram in accordance with the present invention The embodiment shows a graph of the internal electric field that changes at the anode-absorber interface by the strain in the anode and the combined effect of the surface of the Fermi level pinning of the No. A0101 1013265466-0 page 16/28 page 201246560. 6 is an image showing a cross-sectional SEM of a sputtered AZO layer having a cylindrical state; and [0035] FIG. 7 is an X-ray diffraction showing a sputtered oxide layer having a wurtzite structure. A pattern of styles showing unit cells in a natural state and a stress state. [Main component symbol description]

101 substrate [0037] 105 intermediate layer [0038] 107 first interface [0039] 108 Fermi level pinning [0040] 110 AZO layer [0041] 111 Fermi level pinning [0042] 112 second Interface [0043] 115 absorber [0044] 120 buffer layer [0045] 125 window layer 10110861 ^ A〇 101 page 17 / 28 pages 1013265466-0

Claims (1)

201246560 VII. Patent application scope: 1. A method for opening and forming a double-sided enamel film photovoltaic cell, the method comprising: providing a glass substrate having a surface area of the towel layer; forming a film on the surface region a photovoltaic cell comprising: an anode overlying the intermediate layer, an absorber above the anode, a ruthenium layer and a cathode above the Wei g, the window layer and the cathode Having a buffer layer between the absorbers; wherein the anode comprises a 35-doped zinc oxide ((4)) layer to form a first interface with the intermediate layer and a second interface with the absorber, the ΑΖ0 layer Constructed to cause a Fermi level nail violet at the first interface and a strain field from the first interface to the second interface. 2. The method of claim i, wherein the intermediate layer comprises a film comprising: fluorine-doped tin oxide (TF〇), indium tin oxide (IT0), Si3N4, Made of materials selected from Si〇2, pins, and combinations thereof. 3. The method of claim i, wherein the absorber comprises a p-type semiconductor layer made of a CdTe material or a copper indium gallium telluride nGS material. 4. The method of claim i, wherein the layer comprises a heavily doped (10) mass varying from 5xm9cm-3 to lxl〇21 cffi-3. 5. The method of claim i, wherein the Fermi level pinning at the first interface and the strain % from the first interface to the second interface are such The internal electric field strength at the second interface is reduced. 6. The method of claim 5, wherein the reduction of the internal electric field strength at the second interface 10110861#single number A0101 page 18/28 pages 1013265466-0 201246560 is reduced for A barrier that tunnels holes from the absorber to the anode across the second interface. The method of claim 1, wherein the Fermi level pinning at the first interface and the strain field from the first interface to the second interface are such that The direction of the internal electric field at the second interface is reversed. 8. The method of claim 7, wherein the inversion of the direction of the internal electric field at the second interface directly contributes to the empty space from the absorber to the anode at the second interface. The gathering of the points. 9. The method of claim 1, wherein the substrate comprises nano #5 glass. 10. The method of claim 1, wherein the substrate comprises an optional transparent material. 11. A thin film solar device utilizing a strain ΑΖ0 layer for an anode-absorber interface, the device comprising: an optional transparent substrate; an intermediate layer overlying the transparent substrate; an anode layer comprising: forming with the intermediate layer a first interface of an aluminum-doped zinc oxide (ITO) layer; an absorber comprising a copper-indium gallium diselenide having a p-type dopant formed with a second interface of the ΑΖ0 layer; a buffer layer, followed by Subsequent to the buffer layer is a window layer covering the absorber; and a cathode layer covering the window layer; wherein the ΑΖ0 layer causes a strain field in the anode layer and a fee at the first interface The meter level is used to change the internal electric field at the second interface. 1013265466-0 10110861#单单A〇101 Page 19 of 28 201246560 12 The apparatus of claim 2, wherein the optional transparent substrate comprises soda lime glass. 13. The device of claim 5, wherein the intermediate layer comprises a film 'the film is made of fluorine-doped tin oxide (TF0), steel tin oxide (ITO), Si3N4, SiO2. Made of materials selected from molybdenum, molybdenum, and combinations thereof. 14. The device of claim n, wherein the AZ layer comprises a heavily doped 41 species varying from 5乂1019 (:111-3 to 1\1021〇:111-3). The device of claim 2, wherein the strain field in the anode layer and the Fermi level pinning at the first interface cause an internal electric field at the first interface a reduction in strength </ RTI> for facilitating the vacancies from the absorber through the anode layer. The apparatus of claim π, wherein the strain field in the anode layer The Fermi level pinning at the first interface flips the direction of the internal electric field at the first interface for facilitating the accumulation of holes from the absorber through the anode layer. The device of claim 11, wherein the buffer layer comprises a cadmium sulfide having an n-type dopant. 18. The device of claim n, wherein the window layer comprises a transparent layer Conductive oxide, the transparent conductive oxide comprising aluminum doped oxygen The device of claim n, wherein the cathode layer comprises a heavy aluminum-doped zinc oxide. 2) The device of claim n, wherein The absorber comprises a cadmium telluride having a p-type dopant. 1013265466-0 10110861#单号A01〇l Page 20 of 28