TW201244133A - Thin film solar cell and fabricating method thereof - Google Patents

Abstract

A thin film solar cell and fabricating method thereof are applicable to avoid the formation of p-n junction between the contact and photovoltaic transduction layers. The thin film solar cell includes a substrate, a first contact, a photovoltaic transduction layer, a second contact and an oxide layer. The first contact is deposited on the substrate, the photovoltaic transduction layer is deposited on the first contact, the second contact is deposited on the photovoltaic transduction layer, and the oxide layer is deposited between the first contact and the photovoltaic transduction layer so as to prevent the carrier recombining at the interface there in between. By employing the thin film solar cell and fabricating method thereof, the recombination problem which occurred at the interface between two different semiconducting layers of a prior solar cell is solved and meanwhile a simpler and less-cost fabricating method is achieved since it is easily integrated with the solar cell process nowadays.

Description

201244133 6. Technical Field of the Invention The present invention relates to a thin film solar cell and a method of fabricating the same, in particular, a thin film solar cell having an oxide layer disposed between an electrode layer and a photoelectric conversion layer and manufacturing thereof method. [Prior Art] Due to the rapid development of industry, the problem of depletion of fossil fuels and greenhouse gas emissions has been a global concern, and the stable supply of energy has become a major global issue. Compared with traditional coal-fired, gas-fired or nuclear power generation, solar cells use photoelectric or thermoelectric conversion effects to directly convert solar energy into electrical energy, so that carbon dioxide, nitrogen oxides, sulfur oxides, etc. are not accompanied. Greenhouse gases and polluting gases can be used to reduce dependence on fossil fuels while providing a safe and autonomous source of electricity. There are many solar cell technologies known today, after the conversion of solar radiation through the solar cell material, ==,: type = energy battery, which is mainly used to add high-purity semi-conducting materials. (dopants) and present different qualities,

Become a source of available electricity. a samar-based solar-type semiconductor, and bonding a P-N* type half-phase, or doping a five-element element to form N, thus forming a P_N junction

(electron) hole (h〇le) pair. When irradiating a semiconductor having a Ρ·Ν junction, the electrons in a are excited to generate electrons and electricity, and _ are affected by the built-in potential, 201244133 'If the solar cell and the negative current loop are made by wires, Thereby, the solar cells are respectively connected to the two opposite directions of the electric field (loading), which forms a source for generating electricity and supplying the load power. It is known that a solar cell having a tandem type includes a structure such as a substrate, an electrode, and a photoelectric conversion layer in the light-receiving surface of the light. When the sunlight is irradiated from the outside of the substrate to the solar cell, since the electrode layer material is a type semiconductor, when the p-type semiconductor layer in the photoelectric conversion layer is connected to the _transfer body, 'the Ρ·Ν junction surface is formed and The photoelectric conversion layer has a depletion region in the opposite electric field direction, which weakens the flow of the electron hole and increases the recombination rate of the carrier (-ination). The (four) New rise problem of the pure riding solar cell has further affected the solar cell. Photoelectric conversion efficiency. [SUMMARY OF THE INVENTION] In the above, the present invention provides a solar cell and a conversion method to effectively reduce solar energy P_N connection generation and solve the problems of the prior art. σ The present invention relates to a thin film solar cell comprising: a substrate, an -electrode H electrical conversion layer, a second electrode layer and an oxide layer = wherein the 3-electrode layer is disposed on the substrate; and the photoelectric conversion layer is disposed on the first - on the electrode layer; the _ electrode layer is assigned to the job layer; the oxide layer is called between the layer and the light scale layer, and the oxide layer is formed to reduce the sub-electrode bond ratio of the first electrode layer and the photoelectric conversion layer. According to the invention of the present invention, the oxide layer may be cerium oxide (SiO 2 ) having a thickness of from about 0.0044 133 to 10 nm. According to an embodiment of the present invention, wherein the photoelectric conversion layer comprises: a first type semiconductor layer, a first type semiconductor layer, and an intrinsic layer. Wherein, the first type semiconductor layer is adjacent to the second electrode layer; the second type semiconductor layer is adjacent to the oxide layer; and the essential layer is disposed between the first material conductor layer and the second type semiconductor layer. The first electrode layer and the first type semiconductor layer (four) type semiconductor layer, and the second type semiconductor layer is a p type semiconductor layer. According to an embodiment of the invention, wherein the photoelectric conversion layer is selected from at least one of the group consisting of amorphous silicon and microcrystalline silicon? The invention further relates to a method for manufacturing a thin film solar cell, comprising the steps of: forming a first electrode layer on a substrate; forming an oxide layer on the first electrode layer; forming a photoelectric conversion layer on the oxide layer; A second electrode layer is formed on the photoelectric conversion layer. The oxide layer is turned over to lower the carrier binding ratio between the first electrode layer and the photoelectric conversion layer. According to an embodiment of the present invention, the step of forming an oxide layer comprises: plasma-assisted chemical vapor deposition through a carbon dioxide (Plasma Enhance Chemical)

Vapor Deposition, PEC VD). Based on the above, the thin film solar cell and the method for fabricating the same according to the present invention reduce the formation of the PN junction on the interface between the first electrode layer and the photoelectric conversion layer, thereby effectively reducing the junction surface. Carrier binding rate. In addition, the thin film solar cell of the present invention and the method of manufacturing the same can be used with existing solar cells

S 6 201244133 Process integration helps simplify process and reduce costs. The above description of the contents of the present invention, and the following embodiments are used to explain the present invention, the spirit and the principle, and provide a further explanation of the scope of the present invention. The features, implementations, and utilities of the present invention are described in detail with reference to the preferred embodiments. [Embodiment] Hereinafter, the details of the present invention and the advantages thereof will be described in detail in the embodiments, which are sufficient for any skilled person to understand the technology of the present invention and to implement it according to the contents disclosed in the present specification. The related objects and advantages of the present invention will be readily understood by those skilled in the art. "Fig. 1" is a step of a method for manufacturing a thin solar cell according to the present invention, which reduces the probability of formation of the junction of the solar cell towel (9) and maintains the photoelectric conversion of the solar cell. effectiveness. The method for manufacturing a solar cell according to the embodiment includes the following steps: Step S102: forming a first electrode layer on the substrate; Step S104: forming an oxide layer on the first electrode layer; Step S1〇6: Forming a photoelectric conversion layer on the oxide layer; and step S108: forming a second electrode layer on the photoelectric conversion layer. The method for manufacturing a solar cell according to the present invention is to form a silk-bonding layer between the first electrode layer and the photoelectric conversion layer, thereby lowering the carrier bonding ratio (Rec〇mbinationRate) on the contact interface between the two electrodes. For the technical characteristics of this manufacturing method, please refer to the following, and the details are as follows. 201244133 Please refer to FIG. 2, which is a cross-sectional structural view of a thin tan solar cell according to an embodiment of the present invention. As can be seen from FIG. 2, the thin film solar cell 100 includes a substrate 102, a first electrode layer 1〇4 disposed on the substrate 102, an oxide layer 1〇6, a photoelectric conversion layer 1〇8, and a second electrode layer. 110. The first electrode layer 104 is disposed on the substrate 1〇2, and the photoelectric conversion layer is disposed on the first electrode layer 104. The second electrode layer 110 is disposed on the photoelectric conversion layer ι8, and the oxide layer 106 is clamped. It is placed between the first electrode layer 1〇4 and the photoelectric conversion layer 1〇8. In general, a solar cell can be divided into a superstrate structure and a substrate structure depending on the direction of light incident. The thin film solar cell 100 of the present embodiment is, for example, a superstrate ( SUperstrate) Solar photovoltaic components of the structure. As shown in the "Fig. 2", since the cover plate structure means that light is incident from the substrate end, the light L is incident from the substrate 1〇2 side (that is, the lower side in the drawing) to the inside of the thin film solar cell 100. . In an embodiment, the substrate 102 may be a transparent substrate, and the material thereof may be, but not limited to, glass or a transparent resin. Taking this embodiment as an example, based on the photoelectric conversion use of the photoelectric conversion layer 1 〇 8 , the transparentness referred to as the substrate 102 means that the light that can be converted by the photoelectric conversion layer 1 〇 8 passes, and is not transparent only to visible light. At the same time, the transparency here is not 100% for the light to pass through, but rather allows most of the light to penetrate, which is within the scope of the invention. Next, a first electrode layer 1?4 is formed on the substrate 102 to serve as a front electrode of the thin film solar cell 100. The material of the first electrode layer 1〇4 may be selected from the group consisting of Transparent Conductive Oxide (TCO) or 201244133 metal. For example, zinc oxide (Zn0), indium oxide (In2〇3), alumina (A1 doped ZnO, AZO), indium zinc oxide (indium zinc (IV), such as IZO) or other doped five elements to form N Transparent conductive material for semiconductors. The emulsified layer 106 is formed over the first electrode layer and disposed between the first electrode layer 104 and the photoelectric conversion layer 108. The photoelectric conversion layer 1〇8 can be subjected to Radio Frequency Plasma Enhanced Chemical Vapor Deposition (RFPECVD) or Ultra High Frequency Plasma Enhanced Chemical Vapor (Very High Frequency Plasma Enhanced Chemical Vapor).

Deposition, VHF PECVD) or Microwave Plasma Enhanced Chemical Vapor Deposition (MW PECVD), and may be an active layer with a single layer or a tandem structure (ActiveLayer) . In one embodiment, the material of the photoelectric conversion layer 1〇8 is, for example, a single layer of amorphous germanium (Amorphus Silicon, a-Si), a microcrystalline silicon 'm-Si, and a polycrystalline germanium (p〇iy silicon). CdS, CdS, CuInGaSe2, bis iInSe2, CdTe, organic materials, or a stacked structure including at least one of the above materials. In one embodiment, as shown in Fig. 3, the photoelectric conversion layer 10 (10) may be a PIN semiconductor stacked structure having a P-type semiconductor layer 1081, an N-type semiconductor layer 1083, and an intrinsic layer 1 〇 82. In other embodiments, the photoelectric conversion layer 1〇8 may also be a PN semiconductor stacked structure having no intrinsic layer 1082. The present invention does not limit the number or structure of the layers of photoelectric conversion material used in the photovoltaic layer 201244133 conversion layer 108, and those skilled in the art will be able to design them themselves as needed. Since the P-type semiconductor layer 1081 is adjacent to the first electrode layer 104 having an N-type semiconductor, the present invention is mainly applied to the photoelectric conversion layer 108 and the first electrode layer in order to prevent the formation of the Ρ·Ν junction between the two. An oxide layer 1〇6 is formed between 1〇4 to block the bonding of the photoelectric conversion layer 108 and the pair of electron holes on the interface of the first electrode layer 1〇4. According to an embodiment of the present invention, the present invention mainly forms a nano-scale oxide layer 1〇6 on the first electrode layer 104 before the formation of the photoelectric conversion layer 1〇8. The method of forming the oxide layer 106 may include: performing Plasma Enhanced Chemical Vapor Deposition (PECVD) through carbon dioxide (c〇2) to deposit a thin film oxide on the first electrode layer 104. . In general, the material of the thin film oxide may be, but not limited to, cerium oxide (Si 〇 2) and a thickness of between about 0.1 nanometer (nm) and 1 nanometer (nm). Thereby, the oxide layer 106 can be used to effectively prevent the recombination phenomenon (or carrier binding ratio) between the first electrode layer 1〇4 and the photoelectric conversion layer ι8, and since the thickness thereof is relatively thin, the light ray L It is still possible to penetrate the oxide layer 1〇6 and reach the photoelectric conversion layer 1〇8 for photoelectric conversion. Thereafter, the second electrode layer 11 is formed on the photoelectric conversion layer 1 to form a back surface of the thin film solar cell, and the fabrication of the thin film solar cell 100 is completed. The material of the second electrode layer 11A may be selected from the group consisting of transparent conductive oxide (Transparent- tive Oxide' τα) or metal. In the embodiment, the metal is, for example, stellite, silver, Ag, copper, and other metals having electrical conductivity and high reflectivity, or an alloy of the above metals. The transparent conductive oxide can be zinc oxide (Zn0), oxidized steel (ln2〇3): dioxin, tin (Sn〇2), indium tin oxide (IT), indium oxidization Indium zinc oxide (ΙΖΟ), aluminum oxide zinc (A1 d〇ped Ζη〇, αζ(1), etc. ' The method of forming the second electrode layer 110 is, for example, chemical vapor deposition (CVD), physical vapor phase method ( Prepared by PVD), spray coating or other suitable method.

Therefore, in summary, the thin film solar cell proposed by the present invention can prevent the formation of the L junction on both interfaces by forming an oxide layer between the electrode layer and the photoelectric conversion layer, and further can be further advanced. The increase in the series resistance of the battery is avoided, and the photoelectric conversion efficiency of the thin solar cell is maintained. Secondly, the manufacturing method of the thin solar cell proposed by the present invention can be directly oxidized at the time of depositing the P-type base layer to form a thin film oxide on the electrode layer, thereby having the advantages of a fresh process and a cost. Moreover, the method for fabricating the thin film solar cell of the present invention can be integrated with the existing solar cell process, and the process is simple and can effectively improve the component performance of the solar cell. The present invention has been described above with reference to the preferred embodiments thereof, and is not intended to limit the scope of the present invention, and those skilled in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The patent protection scope of the invention is subject to the definition of the scope of the patent application attached to the specification. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flow chart showing the steps of a method of manufacturing a thin film solar cell according to an embodiment of the present invention. 201244133 Fig. 2 is a cross-sectional structural view of a thin film solar cell according to an embodiment of the present invention. Figure 3 is a cross-sectional structural view of a thin film solar cell according to still another embodiment of the present invention. [Major component symbol description] 100 Thin film solar cell 102 Substrate 104 First electrode layer 106 Oxide layer 108. Photoelectric conversion layer 110 Second electrode layer 1081 P type semiconductor layer 1082 Intrinsic layer 1083 N type semiconductor layer

S 12

Claims (1)

201244133 VII. Patent Application Range 1. A thin film solar cell comprising: a substrate; a first electrode layer disposed on the substrate; a photoelectric conversion layer disposed on the first electrode layer; and a second electrode a layer disposed on the ferroelectric conversion layer; and between the carrier binding rate-oxygen layer, and the sa-electrode layer is between the countless electrode layer to reduce the first electrode layer and the photoelectric conversion layer (Rec 〇mbinati〇nRate) 〇2. ^^(4) The objection is that the layer of the sputum is a dream of oxidizing (Si〇2) with a thickness ranging from not more than (10) nanometers. 3. In the case of the first item, the photoelectron layer comprises: a first semiconductor layer adjacent to the second electrode layer; a second semiconductor layer laterally adjacent to the Weihua layer; The intrinsic layer has been placed between the 5 Hz first type semiconductor layer and the second type semiconductor layer. The thin film solar cell according to claim 3, wherein the first-type semiconductor layer and the β-th electrode layer are N-type semiconductor layers, and the second-type semiconductor layer is a p-type semiconductor layer. 5. The thin film solar cell of claim 1, wherein the photoelectric conversion layer is selected from at least one of the group consisting of Amorphous Silicon and Microcrystalline Silicon. 201244133 6. A method for fabricating a thin film solar cell, comprising: forming a first electrode layer on a substrate; forming an oxide layer on the first electrode layer; forming a photoelectric conversion layer on the oxide layer; Forming a second electrode layer on the photoelectric conversion layer; wherein the oxide layer is used to reduce the carrier binding rate between the first electrode layer and the photoelectric conversion layer. 7. The method of manufacturing a thin film solar cell according to claim 6, wherein the step of forming the oxide layer comprises: performing a plasma enhanced chemical vapor deposition (PECVD) by using carbon dioxide. The method of manufacturing a thin film solar cell according to claim 6, wherein the step of forming the photoelectric conversion layer comprises: ???forming a second type semiconductor layer on the oxide layer; forming an intrinsic layer on the second type semiconductor layer And forming a first type semiconductor layer on the intrinsic layer.