WO2015005695A1 - Photovoltaic device - Google Patents

Photovoltaic device Download PDF

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Publication number
WO2015005695A1
WO2015005695A1 PCT/KR2014/006197 KR2014006197W WO2015005695A1 WO 2015005695 A1 WO2015005695 A1 WO 2015005695A1 KR 2014006197 W KR2014006197 W KR 2014006197W WO 2015005695 A1 WO2015005695 A1 WO 2015005695A1
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Prior art keywords
conductive window
photovoltaic device
cell region
light
bandgap energy
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PCT/KR2014/006197
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French (fr)
Korean (ko)
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안상정
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An Sang Jeong
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Publication of WO2015005695A1 publication Critical patent/WO2015005695A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/0256—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by the material
    • H01L31/0264—Inorganic materials
    • H01L31/0328—Inorganic materials including, apart from doping materials or other impurities, semiconductor materials provided for in two or more of groups H01L31/0272 - H01L31/032
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/054—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means
    • H01L31/056—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means the light-reflecting means being of the back surface reflector [BSR] type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/0256—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by the material
    • H01L31/0264—Inorganic materials
    • H01L31/028—Inorganic materials including, apart from doping material or other impurities, only elements of Group IV of the Periodic System
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/0256—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by the material
    • H01L31/0264—Inorganic materials
    • H01L31/0304—Inorganic materials including, apart from doping materials or other impurities, only AIIIBV compounds
    • H01L31/03044—Inorganic materials including, apart from doping materials or other impurities, only AIIIBV compounds comprising a nitride compounds, e.g. GaN
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/06—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by at least one potential-jump barrier or surface barrier
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/52—PV systems with concentrators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/544—Solar cells from Group III-V materials
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/547—Monocrystalline silicon PV cells

Definitions

  • the present disclosure relates generally to photovoltaic devices (PHOTOVOLTAIC DECIVE), and more particularly to photovoltaic devices that improve the problems of conventional glass substrates and / or transmissive conductive oxide films (TCOs).
  • POTOVOLTAIC DECIVE photovoltaic devices
  • TCOs transmissive conductive oxide films
  • the photovoltaic device refers to a device such as a solar cell using a photovoltaic effect.
  • FIG. 1 is a view showing an example of a conventional photovoltaic device, wherein a solar cell composed of a-Si (amorphous silicon) (amorphous silicon) is formed on the upper left side, and a solar cell composed of CdTe is formed on the lower left side.
  • a solar cell composed of a-Si (amorphous silicon) (amorphous silicon) is formed on the upper left side
  • a solar cell composed of CdTe is formed on the lower left side.
  • a cell in which the cell is composed of CuInGaSe 2 (CIGS) on the right side is exemplified.
  • the a-Si solar cell and the CdTe solar cell have a superstrate structure in which light is incident from the substrate 100
  • the CIGS solar cell is a sub-light in which light is incident from the opposite side of the substrate 100. It has a straight structure.
  • the a-Si solar cell is a substrate 100 made of glass, an electrode 200 made of transparent conductive oxide (TCO) such as SnO 2 , a p layer 301 (eg p-SiC), an i-layer as a light absorption region. 302 (eg, ia-Si), n-layer 303 (eg, na-Si), a reflective layer 401, and an electrode 402.
  • TCO transparent conductive oxide
  • the CdTe cell comprises a substrate 100 made of glass, an electrode 200 made of transparent conductive oxide (TCO) such as SnO 2 , an n layer 303 (eg CdS), and a p layer 301 (eg p-CdTe).
  • the CIGS cell comprises a glass substrate 100, an electrode 200 (eg Mo), a p layer 301 (eg p-CuInGaSe 2 ), an n layer 303 (eg n-CdS), a buffer layer 404; For example, ZnO) and the electrode 402.
  • an electrode 200 eg Mo
  • a p layer 301 eg p-CuInGaSe 2
  • an n layer 303 eg n-CdS
  • a buffer layer 404 For example, ZnO
  • FIG. 2 is a diagram illustrating other examples of a conventional photovoltaic device, and includes a plurality of cell regions 310, 320, and 330 in one device (eg, US Patent No. 5,407,491).
  • the cell region 310 located in the upper side, the cell region 320 located in the middle, and the cell region 330 located in the lower side have a large band gap energy from above. It is possible to improve the conversion efficiency of the photovoltaic device.
  • the bandgap energy of various semiconductor materials is as follows (InN: 0.6 eV, Ge: 0.65 eV, Cu (In, Ga) Se 2 : 1.04-1.67 eV, c-Si: 1.12 eV InGaAs: 1.2 eV , InP: 1.35 eV, GaAs: 1.4 eV, CdTe; 1.45 eV, InGaP: 1.86 eV, GaP: 2.25 eV, ZeSe: 2.7 eV, ZnO: 3.37 eV, GaN: 3.4 eV).
  • a photovoltaic device having one cell region or a plurality of cell regions having various band gap energies has been proposed, but a glass substrate is mainly used as the substrate 100.
  • the glass substrate 100 is not suitable for high temperature growth, methods suitable for low temperature growth are mainly used in the manufacture of the thin film solar cell, and there is a limit in achieving high quality of the thin film using high temperature growth. .
  • FIG. 3 is a view showing another example of a conventional photovoltaic device, which includes a substrate 100, an electrode 200, a cell region 300 for converting light into electrical energy, and an electrode 402. Equipped.
  • the rough surface 201 is formed on the electrode 200 (eg, ZnO).
  • the rough surface 201 may be formed during the formation of the electrode 200, or may be formed by surface texturing (eg, wet etching or dry etching) after the formation of the electrode 200. By having a rough surface 200, it is possible to scatter the incident light to increase the amount of light absorption into the device.
  • the cell region 300 is formed on the rough surface 201, there are many constraints (shunting paths, pinholes, local depletion, etc.) to grow a variety of high-quality semiconductor material on the rough surface 201.
  • the electrode 200 In a photovoltaic device with a superstrate structure, the electrode 200 must be conductive, light transmissive, form the base of the cell region 300, and form a high quality rough surface 201. It should be possible.
  • the electrode 200 using the conventional TCO is not easy to satisfy such various requirements, and on the other hand, the substrate 100 made of glass that cannot withstand the high temperature is provided underneath the cell region 300. There are limitations to forming by hot growth techniques.
  • a conductive window having a hexagonal close-packed lattice structure; A conductive window having a rough surface to scatter and having a first bandgap energy; A cell region formed on the conductive window and converting incident light into electrical energy, the cell region having a bandgap energy smaller than the first bandgap energy and having a light absorption region made of a heterogeneous material different from the material constituting the conductive window; And, a photovoltaic device is provided comprising a; a reflective layer for reflecting light incident from the opposite side of the conductive window to the cell region with respect to the cell region.
  • FIG. 1 is a view showing an example of a conventional photovoltaic device
  • FIG. 2 is a view showing other examples of a conventional photovoltaic device
  • FIG. 3 is a view showing still another example of a conventional photovoltaic device
  • FIG. 4 is a diagram illustrating an example of a photovoltaic device according to the present disclosure.
  • FIG. 5 is a photograph showing an example of a rough surface formed on a material having a hexagonal dense lattice structure
  • FIG. 6 illustrates another example of a photovoltaic device according to the present disclosure
  • FIG. 7 and 8 illustrate an example of a method of manufacturing a photovoltaic device according to the present disclosure.
  • the photovoltaic device includes a conductive window 23, a cell region 30, and a reflective layer 41.
  • the conductive window 23 is located on the side where light is incident and has a rough surface 21 that scatters light. Unlike the photovoltaic device shown in FIG. 3, the rough surface 21 is formed outside the device rather than on the cell region 30 side, so that the formation of the rough surface 21 is independent of the formation of the cell region 30. It has the advantage that it can be controlled.
  • the conductive window 23 on which the rough surface 31 is formed is made of a material having a hexagonal dense lattice structure. As shown in FIG.
  • the surface texturing eg, wet etching
  • a material having a hexagonal dense lattice structure eg, GaN, ZnO
  • the N-face GaN, from which the substrate 10 is removed and exposed, is well etched and provides a high quality rough surface 21 as shown.
  • Techniques for surface texturing the conductive window 23, as in FIGS. 3-4, are well known to those skilled in the art.
  • a representative material having a hexagonal dense lattice structure which is represented by a GaN-based compound semiconductor (i.e., Al x Ga y In 1-xy N (0 ⁇ x ⁇ 1,0 ⁇ y ⁇ 1,0 ⁇ x + y ⁇ 1) Group III nitride semiconductors and ZnO-based oxides such as ZnO and MgZnO.
  • a GaN-based compound semiconductor i.e., Al x Ga y In 1-xy N (0 ⁇ x ⁇ 1,0 ⁇ y ⁇ 1,0 ⁇ x + y ⁇ 1)
  • Group III nitride semiconductors and ZnO-based oxides such as ZnO and MgZnO.
  • the substrate 10 may be formed of, for example, sapphire, SiC, Si, Ge, SiGe, GaAs, and the like, and the conductive window 23 is not particularly limited as long as it can be formed, but preferably a material having a high melting point Preferably consisting of sapphire.
  • the cell region 30 is formed on the conductive window 23 and converts light incident through the conductive window 23 into electrical energy.
  • the cell region 30 has a light absorbing region 32, and the light absorbing region 32 is a region in which the conversion into electrical energy of light is actually caused by a photovoltaic effect in the cell region 30.
  • the light absorption region 32 is made of the cell region 30 having an n-layer, i-layer, p-layer, that is, a PIN structure.
  • the depletion region between the p layer and the n layer is used as the light absorption region 32, or a single layer having conductivity different from the conductive window 23 is formed as the cell region 30, thereby conducting It is theoretically possible to use the depletion region between the window 23 and the cell region 30 as the light absorbing region 32.
  • an i layer may be further provided therebetween. That is, the light absorbing region 32 can be made by any method commonly used in the field of photovoltaic devices.
  • the conductive window 23 is made of a material having a bandgap energy greater than that of the light absorbing region 32 so as to prevent incident light from reaching the light absorbing region 32.
  • the light absorption region 32 is formed of Si, Ge, CdTe, CuInGaSe 2 , AlGaInAs, AlGaInP, Group III element- (As, P, N) compounds. Or the like.
  • the reflective layer 41 is formed on the opposite side of the conductive window 23 with respect to the cell region 30, and reflects light incident into the device to the cell region 30.
  • the reflective layer 41 may be made of Ag, Al, Au, Pt, Ni, Mo, Cu, Cr, Ti, TiW, Distributed Bragg Reflector (DBR), Omni-Directional Reflector (ODR), or a combination thereof.
  • DBR Distributed Bragg Reflector
  • ODR Omni-Directional Reflector
  • the electrode 22, the support substrate 40, and the electrode 42 may be further provided, and the support substrate 40 may be bound by the bonding layer 43.
  • the support substrate 40 supports the photovoltaic device after the removal process and the removal of the substrate 10.
  • the bonding layer 43 may be made of Au, Ni, Pd, Pt, Cu, Ti, W, Cr, CrN, TiW, Sn, In, Zn, or a combination thereof.
  • the support substrate 40 may be configured in a rigid form or a flexible form, and may include Sapphire, Si, Refractory Metal (Mo, V, Ti, Cr, etc.), glass, polyimide, and general organic material. And the like.
  • the light absorbing region 30 may be formed by chemical vapor deposition (CVD; for example, MOCVD, ALD, PECVD), and also by physical vapor deposition (PVD; for example, thermal or evaporator, sputtering). Formation is possible.
  • TCO transparent, conducting oxide
  • TCN nitride
  • TCON oxynitride
  • FIG. 6 illustrates another example of a photovoltaic device according to the present disclosure, wherein the photovoltaic device includes two cell regions 30A and 30B. It goes without saying that two or more cell regions can be provided.
  • Reference numeral 35 is a tunnel junction layer.
  • the conductive window 23, the cell region 30A, and the cell region 30B are preferably made of a material having a smaller band gap energy.
  • the conductive window 23 is formed on the substrate 10.
  • a GaN buffer layer is formed at a temperature of about 500 ° C, and then an undoped GaN layer is formed at a temperature of about 1000 ° C, followed by
  • the conductive window 23 may be formed by forming a doped GaN layer.
  • the cell region 30 is formed by a known method according to the selected material, and then the reflective layer 41 is formed.
  • the supporting substrate 40 having the electrode 42 is prepared (the electrode 42 may be formed after wafer bonding or omitted).
  • the supporting substrate 40 is bonded to at least one side of the supporting substrate 40 and the reflective layer 41.
  • the materials constituting layer 43 are formed and then joined.
  • the substrate 10 is removed.
  • the substrate 10 When a transparent substrate 10 such as sapphire or SiC is used, the substrate 10 can be removed by a laser lift-off method (also can be removed by wet etching or mechanical elongation), and Si, Ge, SiGe, In the case of the opaque substrate 10 such as GaAs, it may be removed by wet etching. Finally, as in (d), the rough surface 21 is formed and the electrode 22 is formed.
  • the rough surface 21 may be formed by various methods such as wet etching, dry etching, and mechanical polishing. Preferably it is possible to form a rough surface 21 as in FIG. 5 using a basic etchant (eg KOH, NaOH).
  • the electrode 22 can be formed by stacking Ti / Ni / Au.
  • a conductive window having a hexagonal close-packed lattice structure comprising: a conductive window having a rough surface for scattering light on the side from which light is incident and having a first bandgap energy; ; A cell region formed on the conductive window and converting incident light into electrical energy, the cell region having a bandgap energy smaller than the first bandgap energy and having a light absorption region made of a heterogeneous material different from the material constituting the conductive window; And a reflective layer reflecting light incident from the opposite side of the conductive window to the cell region with respect to the cell region.
  • the window means an entrance through which light comes in.
  • the first bandgap energy When the conductive window is a layer of one material composition, the first bandgap energy has a single value, while when the conductive window is a layer of a plurality of material compositions, the first bandgap energy is the average value of each bandgap energy. It can be defined as.
  • the term "heterogeneous material different from the material constituting the conductive window” means that the GaN-based compound semiconductor (Al x Ga y In 1-xy N (0 ⁇ x ⁇ 1, It means that the light absorption region is made of a material other than 0 ⁇ y ⁇ 1,0 ⁇ x + y ⁇ 1).
  • a photovoltaic device wherein the first bandgap energy is greater than 3 eV.
  • GaN-based compound semiconductors, ZnO-based oxides and MgO-based oxides may satisfy these conditions.
  • a bandgap energy of 3 eV or more it is possible to guide the cell region without absorbing or reflecting most of the light from the sun.
  • a material having a large bandgap energy generally has a high melting point
  • various cell regions applicable at high and low temperatures by using a conductive window having a bandgap energy of 3 eV or more as a base for forming a cell region Forming techniques (PECVD, MOCVD, MBE, HVPE, Sputtering, Evaporator, etc.) can be used.
  • the bandgap energy of the light absorption region is 2 eV or less. This configuration makes it possible to use a material such as Si as the light absorption region.
  • a photovoltaic device characterized in that the cell region contains a compound bonded with a group III-arsenic (As).
  • a photovoltaic device characterized in that the cell region contains a compound bonded by group III-phosphorus (P).
  • a photovoltaic device wherein the cell region contains a compound bonded with Cu-In-Ga-S (Se).
  • Photovoltaic devices eg, ZnO, MgZnO, MgO
  • the conductive window is made of an oxide containing zinc (Zn) or magnesium (Mg).
  • the cell region may be made of an organic material such as a dye-sensitized die.
  • the present disclosure it is possible to improve the problems caused by the use of the existing glass substrate and / or the transparent conductive oxide film (TCO).
  • photovoltaic device it is possible to provide a substrate or a base capable of growing a cell region at a high temperature.
  • photovoltaic device According to another photovoltaic device according to the present disclosure, it is possible to make a photovoltaic device having a rough surface that can solve problems such as shunting paths, pinholes, local depletion, and the like.

Abstract

The present disclosure relates to a photovoltaic device comprising: a conductive window having a hexagonal close-packed lattice structure, a rough surface for scattering light at an incidence side, and a first band gap energy; a cell area which is formed on the conductive window, converts introduced light into electric energy, and has a photo absorption area having band gap energy lower than the first band gap energy and made of a material different from a material constituting the conductive window; and a reflection layer for reflecting light introduced from the side opposite to the conductive window on the basis of the cell area, toward the cell area.

Description

광기전력 소자Photovoltaic devices
본 개시(Disclosure)는 전체적으로 광기전력 소자(PHOTOVOLTAIC DECIVE)에 관한 것으로, 특히 기존 유리 기판 및/또는 투광성 전도 산화막(TCO)의 문제점을 개선한 광기전력 소자에 관한 것이다.The present disclosure relates generally to photovoltaic devices (PHOTOVOLTAIC DECIVE), and more particularly to photovoltaic devices that improve the problems of conventional glass substrates and / or transmissive conductive oxide films (TCOs).
여기서, 광기전력 소자는 광기전력 효과(Photovoltaic Effect)를 이용하는 솔라셀과 같은 소자를 일컫는다.Here, the photovoltaic device refers to a device such as a solar cell using a photovoltaic effect.
여기서는, 본 개시에 관한 배경기술이 제공되며, 이들이 반드시 공지기술을 의미하는 것은 아니다(This section provides background information related to the present disclosure which is not necessarily prior art).This section provides background information related to the present disclosure which is not necessarily prior art.
도 1은 종래의 광기전력 소자의 예를 나타내는 도면으로서, 좌측 상단에, a-Si(amorphous-Silicon; 비결정질 실리콘)을 구성 물질로 하는 솔라셀이, 좌측 하단에, CdTe를 구성 물질로 하는 솔라셀이, 우측에 CuInGaSe2(CIGS)를 구성 물질로 하는 솔라셀이 예시되어 있다. 도 1에서, a-Si 솔라셀과 CdTe 솔라셀은 기판(100)으로부터 빛이 입사되는 수퍼스트레이트(Superstrate) 구조로 되어 있으며, CIGS 솔라셀은 기판(100)의 반대 측에서 빛이 입사되는 서브스트레이트(Substrate) 구조로 되어 있다. a-Si 솔라셀은 글라스로 된 기판(100), TCO(Transparent Conductive Oxide; 예: SnO2)로 된 전극(200), p층(301; 예: p-SiC), 광 흡수 영역으로서 i층(302; 예: i-a-Si), n층(303; 예: n-a-Si), 반사층(401) 그리고, 전극(402) 등으로 구성될 수 있다. CdTe 솔라셀은 글라스로 된 기판(100), TCO(Transparent Conductive Oxide; 예: SnO2)로 된 전극(200), n층(303; 예: CdS), p층(301; 예: p-CdTe), 버퍼층(404) 그리고, 전극(402) 등으로 구성될 수 있다. CIGS 솔라셀은 글라스로 된 기판(100), 전극(200; 예: Mo), p층(301; 예: p-CuInGaSe2), n층(303; 예: n-CdS), 버퍼층(404; 예: ZnO) 그리고, 전극(402) 등으로 구성될 수 있다.1 is a view showing an example of a conventional photovoltaic device, wherein a solar cell composed of a-Si (amorphous silicon) (amorphous silicon) is formed on the upper left side, and a solar cell composed of CdTe is formed on the lower left side. A cell in which the cell is composed of CuInGaSe 2 (CIGS) on the right side is exemplified. In FIG. 1, the a-Si solar cell and the CdTe solar cell have a superstrate structure in which light is incident from the substrate 100, and the CIGS solar cell is a sub-light in which light is incident from the opposite side of the substrate 100. It has a straight structure. The a-Si solar cell is a substrate 100 made of glass, an electrode 200 made of transparent conductive oxide (TCO) such as SnO 2 , a p layer 301 (eg p-SiC), an i-layer as a light absorption region. 302 (eg, ia-Si), n-layer 303 (eg, na-Si), a reflective layer 401, and an electrode 402. The CdTe cell comprises a substrate 100 made of glass, an electrode 200 made of transparent conductive oxide (TCO) such as SnO 2 , an n layer 303 (eg CdS), and a p layer 301 (eg p-CdTe). ), A buffer layer 404, and an electrode 402. The CIGS cell comprises a glass substrate 100, an electrode 200 (eg Mo), a p layer 301 (eg p-CuInGaSe 2 ), an n layer 303 (eg n-CdS), a buffer layer 404; For example, ZnO) and the electrode 402.
도 2는 종래의 광기전력 소자의 다른 예들을 나타내는 도면으로서, 하나의 소자 내에 복수의 셀 영역(310,320,330)이 구비되어 있다(예: 미국 등록특허공보 제5,407,491호). 빛이 소자의 위쪽으로부터 입사될 때 상측에 위치하는 셀 영역(310), 중간에 위치하는 셀 영역(320), 하측에 위치하는 셀 영역(330) 순으로, 위에서부터 큰 밴드갭 에너지를 가지도록 구성되어 광기전력 소자의 전환 효율을 향상시킬 수 있게 된다. 예를 들어, 여러 반도체 물질의 밴드갭 에너지는 다음과 같다(InN: 0.6eV, Ge: 0.65eV, Cu(In,Ga)Se2: 1.04-1.67eV, c-Si: 1.12eV InGaAs: 1.2eV, InP: 1.35eV, GaAs: 1.4eV, CdTe; 1.45eV, InGaP: 1.86eV, GaP: 2.25eV, ZeSe: 2.7eV, ZnO: 3.37eV, GaN: 3.4eV).FIG. 2 is a diagram illustrating other examples of a conventional photovoltaic device, and includes a plurality of cell regions 310, 320, and 330 in one device (eg, US Patent No. 5,407,491). When light is incident from the top of the device, the cell region 310 located in the upper side, the cell region 320 located in the middle, and the cell region 330 located in the lower side have a large band gap energy from above. It is possible to improve the conversion efficiency of the photovoltaic device. For example, the bandgap energy of various semiconductor materials is as follows (InN: 0.6 eV, Ge: 0.65 eV, Cu (In, Ga) Se 2 : 1.04-1.67 eV, c-Si: 1.12 eV InGaAs: 1.2 eV , InP: 1.35 eV, GaAs: 1.4 eV, CdTe; 1.45 eV, InGaP: 1.86 eV, GaP: 2.25 eV, ZeSe: 2.7 eV, ZnO: 3.37 eV, GaN: 3.4 eV).
도 1 및 도 2에서와 같이, 다양한 밴드갭 에너지를 가지는 하나의 셀 영역 또는 복수의 셀 영역을 가지는 광기전력 소자가 제시되고 있지만, 기판(100)으로 주로 글라스 기판이 이용되고 있다. 그러나 글라스로 된 기판(100)은 고온 성장에 적합하지 않아, 박막 솔라셀의 제조에 있어 주로 저온 성장에 적합한 방법들이 이용되고 있으며, 고온 성장을 이용하여 박막의 양질화를 도모하는 데는 한계가 있다.As shown in FIGS. 1 and 2, a photovoltaic device having one cell region or a plurality of cell regions having various band gap energies has been proposed, but a glass substrate is mainly used as the substrate 100. However, since the glass substrate 100 is not suitable for high temperature growth, methods suitable for low temperature growth are mainly used in the manufacture of the thin film solar cell, and there is a limit in achieving high quality of the thin film using high temperature growth. .
도 3은 종래의 광기전력 소자의 또 다른 예를 나타내는 도면으로서, 광기전력 소자는 기판(100), 전극(200), 빛을 전기 에너지로 전환하는 셀 영역(300), 그리고 전극(402)을 구비한다. 도 1에 도시된 광기전력 소자와 달리, 전극(200; 예: ZnO)에 거친 표면(201)이 형성되어 있다. 거친 표면(201)은 전극(200)의 형성 과정에서 형성되거나, 전극(200)의 형성 후 Surface Texturing 기술(예: Wet Etching 또는 Dry Etching)에 의해 형성될 수 있다. 거친 표면(200)을 구비함으로써, 입사되는 빛을 산란시켜 소자 내로의 광 흡수량을 증가시킬 수 있다. 그러나 거친 표면(201) 위에 셀 영역(300)이 형성되기 때문에, 다양한 양질의 반도체 물질을 거친 표면(201) 위에 성장시키기에는 많은 제약(Shunting path, pinholes, local depletion 등)이 따른다. 수퍼스트레이트(Superstrate) 구조의 광기전력 소자에 있어서, 전극(200)은 도전성이어야 하며, 투광성이어야 하고, 셀 영역(300) 형성의 기초(Base)가 되고, 양질의 거친 표면(201)을 형성할 수 있어야 한다. 그러나, 기존의 TCO를 이용한 전극(200)으로는 이러한 다양한 요구를 만족시키기 쉽지 않으며, 한편으로 그 아래에 높은 온도에서 견디지 못하는 글라스로 된 기판(100)이 별도로 구비됨으로써, 셀 영역(300)을 고온 성장 기법으로 형성하기에는 제약이 따른다.3 is a view showing another example of a conventional photovoltaic device, which includes a substrate 100, an electrode 200, a cell region 300 for converting light into electrical energy, and an electrode 402. Equipped. Unlike the photovoltaic device shown in FIG. 1, the rough surface 201 is formed on the electrode 200 (eg, ZnO). The rough surface 201 may be formed during the formation of the electrode 200, or may be formed by surface texturing (eg, wet etching or dry etching) after the formation of the electrode 200. By having a rough surface 200, it is possible to scatter the incident light to increase the amount of light absorption into the device. However, since the cell region 300 is formed on the rough surface 201, there are many constraints (shunting paths, pinholes, local depletion, etc.) to grow a variety of high-quality semiconductor material on the rough surface 201. In a photovoltaic device with a superstrate structure, the electrode 200 must be conductive, light transmissive, form the base of the cell region 300, and form a high quality rough surface 201. It should be possible. However, the electrode 200 using the conventional TCO is not easy to satisfy such various requirements, and on the other hand, the substrate 100 made of glass that cannot withstand the high temperature is provided underneath the cell region 300. There are limitations to forming by hot growth techniques.
이에 대하여 '발명의 실시를 위한 구체적인 내용'의 후단에 기술한다.This is described later in the section titled 'Details of the Invention.'
여기서는, 본 개시의 전체적인 요약(Summary)이 제공되며, 이것이 본 개시의 외연을 제한하는 것으로 이해되어서는 아니된다(This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features).This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all, provided that this is a summary of the disclosure. of its features).
본 개시에 따른 일 태양에 의하면(According to one aspect of the present disclosure), 육방 조밀 격자 구조(Hexagonal Close-Packed Lattice Structure)를 가지는 도전성 윈도우(Conductive Window);로서, 빛이 입사되는 측에 빛을 산란시키는 거친 표면을 가지며, 제1 밴드갭 에너지를 가지는 도전성 윈도우; 도전성 윈도우 상에 형성되며, 입사된 빛을 전기 에너지로 전환하고, 제1 밴드갭 에너지보다 작은 밴드갭 에너지를 가지면서 도전성 윈도우를 구성하는 물질과 다른 이종 물질로 된 광 흡수 영역을 가지는 셀 영역; 그리고, 셀 영역을 기준으로 도전성 윈도우의 반대 측에서 입사된 빛을 셀 영역으로 반사하는 반사층;을 포함하는 것을 특징으로 하는 광기전력 소자가 제공된다.According to one aspect of the present disclosure (According to one aspect of the present disclosure), a conductive window having a hexagonal close-packed lattice structure; A conductive window having a rough surface to scatter and having a first bandgap energy; A cell region formed on the conductive window and converting incident light into electrical energy, the cell region having a bandgap energy smaller than the first bandgap energy and having a light absorption region made of a heterogeneous material different from the material constituting the conductive window; And, a photovoltaic device is provided comprising a; a reflective layer for reflecting light incident from the opposite side of the conductive window to the cell region with respect to the cell region.
이에 대하여 '발명의 실시를 위한 구체적인 내용'의 후단에 기술한다.This is described later in the section titled 'Details of the Invention.'
도 1은 종래의 광기전력 소자의 예를 나타내는 도면,1 is a view showing an example of a conventional photovoltaic device,
도 2는 종래의 광기전력 소자의 다른 예들을 나타내는 도면,2 is a view showing other examples of a conventional photovoltaic device,
도 3은 종래의 광기전력 소자의 또 다른 예를 나타내는 도면,3 is a view showing still another example of a conventional photovoltaic device;
도 4는 본 개시에 따른 광기전력 소자의 일 예를 나타내는 도면,4 is a diagram illustrating an example of a photovoltaic device according to the present disclosure;
도 5는 육방 조밀 격자 구조를 가지는 물질에 형성된 거친 표면의 예를 나타내는 사진,5 is a photograph showing an example of a rough surface formed on a material having a hexagonal dense lattice structure;
도 6은 본 개시에 따른 광기전력 소자의 다른 예를 나타내는 도면,6 illustrates another example of a photovoltaic device according to the present disclosure;
도 7 및 도 8은 본 개시에 따라 광기전력 소자를 제조하는 방법의 일 예를 나타내는 도면.7 and 8 illustrate an example of a method of manufacturing a photovoltaic device according to the present disclosure.
이하, 본 개시를 첨부된 도면을 참고로 하여 자세하게 설명한다(The present disclosure will now be described in detail with reference to the accompanying drawing(s)). The present disclosure will now be described in detail with reference to the accompanying drawing (s).
도 4는 본 개시에 따른 광기전력 소자의 일 예를 나타내는 도면으로서, 광기전력 소자는 도전성 윈도우(23), 셀 영역(30), 그리고 반사층(41)을 포함한다. 도전성 윈도우(23)는 빛이 입사되는 측에 위치되며, 빛을 산란시키는 거친 표면(21)을 가진다. 도 3에 도시된 광기전력 소자와 달리, 거친 표면(21)이 셀 영역(30) 측이 아니라 소자의 외측에 형성되어 있어, 거친 표면(21)의 형성이 셀 영역(30)의 형성과 독립적으로 제어될 수 있는 이점을 가진다. 본 개시에 있어서, 거친 표면(31)이 형성되는 도전성 윈도우(23)는 육방 조밀 격자 구조를 가지는 물질로 이루어진다. 도 5에 도시된 바와 같이, 육방 조밀 격자 구조를 가지는 물질(예: GaN, ZnO)을 표면 텍스쳐링(Surface Texturing; 예: Wet Etching)한 표면은 피라미드 형상을 가지는 매우 규칙적인 돌기들로 이루어져 산란에 매우 유리한 거친 표면(21)을 형성한다. 기판(10)이 제거되고 노출되는 N-face GaN은 습식 식각이 잘 되며, 도시와 같이 양질의 거친 표면(21)을 제공한다. 도전성 윈도우(23)를, 도 3 내지 도 4에서와 같이, 표면 텍스쳐링하는 기술 자체는 당업자에게 이미 잘 알려져 있다. 육방 조밀 격자 구조를 가지는 대표적인 물질로서, GaN계 화합물 반도체(즉, AlxGayIn1-x-yN(0≤x≤1,0≤y≤1,0≤x+y≤1)로 표현되는 3족 질화물 반도체)와 ZnO계 산화물(예: ZnO, MgZnO)을 들 수 있다. 상세한 제조 방법은 후술하겠지만, 도전성 윈도우(23)는 기판(10) 위에 형성되며, 기판(10)은 광기전력 소자의 다른 요소들이 형성된 후에, 레이저 리프트-오프법, 기계적 연마, 습식 식각 등의 방법으로 도전성 윈도우(23)로부터 제거된다. 기판(10)은 예를 들어, 사파이어, SiC, Si, Ge, SiGe, GaAs 등으로 이루어질 수 있으며, 도전성 윈도우(23)의 형성이 가능하다면 특별히 제한이 있는 것은 아니지만, 바람직하게는 녹는점이 높은 물질로 이루어지는 것이 바람직하다(예: 사파이어). 셀 영역(30)은 도전성 윈도우(23) 상에 형성되며, 도전성 윈도우(23)를 통해 입사된 빛을 전기 에너지로 전환한다. 셀 영역(30)은 광 흡수 영역(32)을 가지며, 광 흡수 영역(32)은 셀 영역(30) 내에서 광기전력 효과(Photovoltaic Effect)에 의해 빛의 전기 에너지로 전환이 실제로 일어나는 영역이다. 바람직하게는 광 흡수 영역(32)은 셀 영역(30)을 n층, i층, p층, 즉 P-I-N 구조로 하여 만들어진다. 그러나, p층과 n층을 구비하여 이 사이의 공핍 영역을 광 흡수 영역(32)로 이용하거나, 도전성 윈도우(23)와 다른 도전성을 가지는 단일의 층을 셀 영역(30)으로 구성하여, 도전성 윈도우(23)와 셀 영역(30) 사이의 공핍 영역을 광 흡수 영역(32)으로 이용하는 것이 이론적으로 가능하다. 또한 이들 사이에 i층이 더 구비되어도 좋다. 즉, 광 흡수 영역(32)은 광기전력 소자 분야에서 통용되는 어떠한 방법에 의해서도 만들어질 수 있다. 도전성 윈도우(23)는 입사된 광이 광 흡수 영역(32)에 이르는 것을 방해하지 않도록 광 흡수 영역(32)보다 큰 밴드갭 에너지를 가지는 물질로 구성된다. 예를 들어, 도전성 윈도우(23)가 n형 GaN으로 이루어질 때, 광 흡수 영역(32)은 Si, Ge, CdTe, CuInGaSe2, AlGaInAs, AlGaInP, 그룹 3족 원소-(As, P, N) 화합물 등으로 이루어질 수 있다. 반사층(41)은 셀 영역(30)을 기준으로 도전성 윈도우(23)의 반대 측에 형성되며, 소자 내로 입사된 빛을 셀 영역(30)으로 반사한다. 예를 들어 반사층(41)은 Ag, Al, Au, Pt, Ni, Mo, Cu, Cr, Ti, TiW, DBR(Distributed Bragg Reflector), ODR(Omni-Directional Reflector) 또는 이들의 조합으로 이루어질 수 있다. 또한 반사층(41)과 셀 영역(30) 사이에 ITO, IO, TO, ZnO, ZITO, SiO2, TiN와 같은 투광성 막을 추가하는 것도 가능하다. 필요에 따라, 전극(22), 지지 기판(40), 전극(42)이 더 구비될 수 있으며, 지지 기판(40)은 본딩층(43)에 의해 결할될 수 있다. 지지 기판(40)은 기판(10)의 제거 과정 및 제거 후에 광기전력 소자를 지지하는 역할을 한다. 예를 들어, 본딩층(43)은 Au, Ni, Pd, Pt, Cu, Ti, W, Cr, CrN, TiW, Sn, In, Zn 또는 이들의 조합으로 이루어질 수 있다. 지지 기판(40)은 휨이 없는(rigid) 형태 또는 휨이 가능한(flexible) 형태로 구성될 수 있으며, Sapphire, Si, Refractory Metal(Mo, V, Ti, Cr 등), 글라스, Polyimide, 일반 유기물 등으로 구성될 수 있다. 광 흡수 영역(30)은 화학증기증착법(CVD; 예: MOCVD, ALD, PECVD)으로 형성가능하며, 또한 물리증기증착법(PVD; 예: 열 또는 이빔 증착법(Evaporator), 스퍼터링(Sputtering))으로도 형성이 가능하다. 또한 필요에 따라, 투명하고(Transparent), 전기가 통하는(Conducting) 산화물(TCO; ITO, SnO2, In2O3, InZnO, etc) 또는 질화물(TCN; TiN, etc) 또는 산화질화물(TCON, ITON, etc)을 우선 형성하고 Si 등의 셀 영역(30) 물질을 형성하는 것도 가능하다.4 is a diagram illustrating an example of a photovoltaic device according to the present disclosure, wherein the photovoltaic device includes a conductive window 23, a cell region 30, and a reflective layer 41. The conductive window 23 is located on the side where light is incident and has a rough surface 21 that scatters light. Unlike the photovoltaic device shown in FIG. 3, the rough surface 21 is formed outside the device rather than on the cell region 30 side, so that the formation of the rough surface 21 is independent of the formation of the cell region 30. It has the advantage that it can be controlled. In the present disclosure, the conductive window 23 on which the rough surface 31 is formed is made of a material having a hexagonal dense lattice structure. As shown in FIG. 5, the surface texturing (eg, wet etching) of a material having a hexagonal dense lattice structure (eg, GaN, ZnO) is composed of very regular protrusions having a pyramidal shape. It forms a very advantageous rough surface 21. The N-face GaN, from which the substrate 10 is removed and exposed, is well etched and provides a high quality rough surface 21 as shown. Techniques for surface texturing the conductive window 23, as in FIGS. 3-4, are well known to those skilled in the art. A representative material having a hexagonal dense lattice structure, which is represented by a GaN-based compound semiconductor (i.e., Al x Ga y In 1-xy N (0≤x≤1,0≤y≤1,0≤x + y≤1) Group III nitride semiconductors and ZnO-based oxides such as ZnO and MgZnO. A detailed manufacturing method will be described later, but the conductive window 23 is formed on the substrate 10, the substrate 10 after the other elements of the photovoltaic device is formed, methods such as laser lift-off method, mechanical polishing, wet etching, etc. Is removed from the conductive window 23. The substrate 10 may be formed of, for example, sapphire, SiC, Si, Ge, SiGe, GaAs, and the like, and the conductive window 23 is not particularly limited as long as it can be formed, but preferably a material having a high melting point Preferably consisting of sapphire. The cell region 30 is formed on the conductive window 23 and converts light incident through the conductive window 23 into electrical energy. The cell region 30 has a light absorbing region 32, and the light absorbing region 32 is a region in which the conversion into electrical energy of light is actually caused by a photovoltaic effect in the cell region 30. Preferably, the light absorption region 32 is made of the cell region 30 having an n-layer, i-layer, p-layer, that is, a PIN structure. However, the depletion region between the p layer and the n layer is used as the light absorption region 32, or a single layer having conductivity different from the conductive window 23 is formed as the cell region 30, thereby conducting It is theoretically possible to use the depletion region between the window 23 and the cell region 30 as the light absorbing region 32. In addition, an i layer may be further provided therebetween. That is, the light absorbing region 32 can be made by any method commonly used in the field of photovoltaic devices. The conductive window 23 is made of a material having a bandgap energy greater than that of the light absorbing region 32 so as to prevent incident light from reaching the light absorbing region 32. For example, when the conductive window 23 is made of n-type GaN, the light absorption region 32 is formed of Si, Ge, CdTe, CuInGaSe 2 , AlGaInAs, AlGaInP, Group III element- (As, P, N) compounds. Or the like. The reflective layer 41 is formed on the opposite side of the conductive window 23 with respect to the cell region 30, and reflects light incident into the device to the cell region 30. For example, the reflective layer 41 may be made of Ag, Al, Au, Pt, Ni, Mo, Cu, Cr, Ti, TiW, Distributed Bragg Reflector (DBR), Omni-Directional Reflector (ODR), or a combination thereof. . It is also possible to add a light transmissive film, such as ITO, IO, TO, ZnO, ZITO, SiO 2 , TiN, between the reflective layer 41 and the cell region 30. If necessary, the electrode 22, the support substrate 40, and the electrode 42 may be further provided, and the support substrate 40 may be bound by the bonding layer 43. The support substrate 40 supports the photovoltaic device after the removal process and the removal of the substrate 10. For example, the bonding layer 43 may be made of Au, Ni, Pd, Pt, Cu, Ti, W, Cr, CrN, TiW, Sn, In, Zn, or a combination thereof. The support substrate 40 may be configured in a rigid form or a flexible form, and may include Sapphire, Si, Refractory Metal (Mo, V, Ti, Cr, etc.), glass, polyimide, and general organic material. And the like. The light absorbing region 30 may be formed by chemical vapor deposition (CVD; for example, MOCVD, ALD, PECVD), and also by physical vapor deposition (PVD; for example, thermal or evaporator, sputtering). Formation is possible. Also, if necessary, transparent, conducting oxide (TCO; ITO, SnO 2 , In 2 O 3 , InZnO, etc) or nitride (TCN; TiN, etc) or oxynitride (TCON, It is also possible to first form ITON, etc. and to form a cell region 30 material such as Si.
도 6은 본 개시에 따른 광기전력 소자의 다른 예를 나타내는 도면으로서, 광 기전력 소자는 두 개의 셀 영역(30A,30B)을 구비한다. 2개 이상의 셀 영역을 구비할 수 있음을 물론이다. 미설명 부호 35는 터널 정션(Tunnel Junction)층이다. 도전성 윈도우(23), 셀 영역(30A), 셀 영역(30B)으로 갈수록 작은 밴드갭 에너지를 가지는 물질로 이루어지는 것이 바람직하다.6 illustrates another example of a photovoltaic device according to the present disclosure, wherein the photovoltaic device includes two cell regions 30A and 30B. It goes without saying that two or more cell regions can be provided. Reference numeral 35 is a tunnel junction layer. The conductive window 23, the cell region 30A, and the cell region 30B are preferably made of a material having a smaller band gap energy.
도 7 및 도 8은 본 개시에 따라 광기전력 소자를 제조하는 방법의 일 예를 나타내는 도면으로서, 먼저 (a)에서와 같이, 기판(10) 상에 도전성 윈도우(23)를 형성한다. 예를 들어, 사파이어로 된 기판(10) 위에, MOCVD법을 이용하여, 500℃ 전후의 온도에서 GaN 버퍼층을 형성한 다음, 1000℃ 전후의 온도에서 도핑되지 않은 GaN층을 형성한 다음, Si으로 도핑된 GaN층을 형성하여 도전성 윈도우(23)를 형성할 수 있다.7 and 8 illustrate an example of a method of manufacturing a photovoltaic device according to the present disclosure. First, as in (a), the conductive window 23 is formed on the substrate 10. For example, on the substrate 10 made of sapphire, by using the MOCVD method, a GaN buffer layer is formed at a temperature of about 500 ° C, and then an undoped GaN layer is formed at a temperature of about 1000 ° C, followed by The conductive window 23 may be formed by forming a doped GaN layer.
다음으로, (b)에서와 같이, 선택된 물질에 따르는 주지의 방법으로 셀 영역(30)을 형성한 다음, 반사층(41)을 형성한다. 별도로 전극(42)을 구비한 지지 기판(40)을 준비하고(전극(42)은 웨이퍼 본딩 후에 형성되거나, 생략될 수 있다.), 지지 기판(40)과 반사층(41) 중 적어도 일측에 본딩층(43)을 구성하는 물질을 형성한 다음 이들을 접합한다. 다음으로, (c)에서와 같이, 기판(10)을 제거한다. 사파이어, SiC와 같이 투명한 기판(10)이 사용되는 경우에는 레이저 리프트-오프법에 의해 기판(10)을 제거할 수 있으며(습식 식각 또는 기계적 연만에 의해 제거도 가능), Si,Ge, SiGe, GaAs와 같은 불투명한 기판(10)의 경우에 습식 식각을 통해 제거할 수 있다. 마지막으로, (d)에서와 같이, 거친 표면(21)을 형성하고, 전극(22)을 형성한다. 거친 표면(21)은 습식 식각, 건식 식각, 기계적 연마 등 다양한 방법에 의해 형성될 수 있다. 바람직하게는 염기성 에천트(예: KOH, NaOH)를 이용하여 도 5에서와 같은 거친 표면(21)을 형성하는 것이 가능하다. 전극(22)은 Ti/Ni/Au의 적층으로 형성하는 것이 가능하다.Next, as in (b), the cell region 30 is formed by a known method according to the selected material, and then the reflective layer 41 is formed. Separately, the supporting substrate 40 having the electrode 42 is prepared (the electrode 42 may be formed after wafer bonding or omitted). The supporting substrate 40 is bonded to at least one side of the supporting substrate 40 and the reflective layer 41. The materials constituting layer 43 are formed and then joined. Next, as in (c), the substrate 10 is removed. When a transparent substrate 10 such as sapphire or SiC is used, the substrate 10 can be removed by a laser lift-off method (also can be removed by wet etching or mechanical elongation), and Si, Ge, SiGe, In the case of the opaque substrate 10 such as GaAs, it may be removed by wet etching. Finally, as in (d), the rough surface 21 is formed and the electrode 22 is formed. The rough surface 21 may be formed by various methods such as wet etching, dry etching, and mechanical polishing. Preferably it is possible to form a rough surface 21 as in FIG. 5 using a basic etchant (eg KOH, NaOH). The electrode 22 can be formed by stacking Ti / Ni / Au.
이하 본 개시의 다양한 실시 형태에 대하여 설명한다.Hereinafter, various embodiments of the present disclosure will be described.
(1) 육방 조밀 격자 구조(Hexagonal Close-Packed Lattice Structure)를 가지는 도전성 윈도우(Conductive Window);로서, 빛이 입사되는 측에 빛을 산란시키는 거친 표면을 가지며, 제1 밴드갭 에너지를 가지는 도전성 윈도우; 도전성 윈도우 상에 형성되며, 입사된 빛을 전기 에너지로 전환하고, 제1 밴드갭 에너지보다 작은 밴드갭 에너지를 가지면서 도전성 윈도우를 구성하는 물질과 다른 이종 물질로 된 광 흡수 영역을 가지는 셀 영역; 그리고, 셀 영역을 기준으로 도전성 윈도우의 반대 측에서 입사된 빛을 셀 영역으로 반사하는 반사층;을 포함하는 것을 특징으로 하는 광기전력 소자. 여기서, 윈도우는 빛이 들어오는 입구를 의미한다. 도전성 윈도우가 하나의 물질 조성으로 된 층일 때, 제1 밴드갭 에너지는 단일의 값을 가지지만, 도전성 윈도우가 복수의 물질 조성으로 된 층일 때, 제1 밴드갭 에너지는 각각의 밴드갭 에너지의 평균값으로 정의될 수 있다. '도전성 윈도우를 구성하는 물질과 다른 이종 물질'이라는 것은, 예를 들어, 도전성 윈도우가 GaN계 화합물 반도체로 이루어질 때 GaN계 화합물 반도체(AlxGayIn1-x-yN(0≤x≤1,0≤y≤1,0≤x+y≤1)가 아닌 물질로 광 흡수 영역이 이루어짐을 의미한다.(1) a conductive window having a hexagonal close-packed lattice structure, comprising: a conductive window having a rough surface for scattering light on the side from which light is incident and having a first bandgap energy; ; A cell region formed on the conductive window and converting incident light into electrical energy, the cell region having a bandgap energy smaller than the first bandgap energy and having a light absorption region made of a heterogeneous material different from the material constituting the conductive window; And a reflective layer reflecting light incident from the opposite side of the conductive window to the cell region with respect to the cell region. Here, the window means an entrance through which light comes in. When the conductive window is a layer of one material composition, the first bandgap energy has a single value, while when the conductive window is a layer of a plurality of material compositions, the first bandgap energy is the average value of each bandgap energy. It can be defined as. The term "heterogeneous material different from the material constituting the conductive window" means that the GaN-based compound semiconductor (Al x Ga y In 1-xy N (0≤x≤1, It means that the light absorption region is made of a material other than 0≤y≤1,0≤x + y≤1).
(2) 제1 밴드갭 에너지는 3eV보다 큰 것을 특징으로 하는 광기전력 소자. GaN계 화합물 반도체, ZnO계 산화물 및 MgO계 산화물이 이러한 조건을 만족할 수 있다. 3eV 이상의 밴드갭 에너지를 가짐으로써, 태양으로부터 대부분의 빛을 흡수 또는 반사시키지 않고 셀 영역으로 안내할 수 있게 된다. 또한 큰 밴드갭 에너지를 가지는 물질이 높은 녹는점을 가지는 것이 일반적이므로, 3eV이상의 밴드갭 에너지를 가지는 도전성 윈도우를 셀 영역을 형성하는 기초(base)로 사용함으로써, 고온 및 저온에서 적용가능한 다양한 셀 영역 형성 기법(PECVD법, MOCVD법, MBE법, HVPE법, Sputtering, Evaporator 등)을 사용할 수 있게 된다. (2) A photovoltaic device, wherein the first bandgap energy is greater than 3 eV. GaN-based compound semiconductors, ZnO-based oxides and MgO-based oxides may satisfy these conditions. By having a bandgap energy of 3 eV or more, it is possible to guide the cell region without absorbing or reflecting most of the light from the sun. In addition, since a material having a large bandgap energy generally has a high melting point, various cell regions applicable at high and low temperatures by using a conductive window having a bandgap energy of 3 eV or more as a base for forming a cell region Forming techniques (PECVD, MOCVD, MBE, HVPE, Sputtering, Evaporator, etc.) can be used.
(3) 광 흡수 영역의 밴드갭 에너지는 2eV이하인 것을 특징으로 하는 광기전력 소자. 이러한 구성을 통해 Si과 같은 물질을 광 흡수 영역으로 사용할 수 있다.(3) The bandgap energy of the light absorption region is 2 eV or less. This configuration makes it possible to use a material such as Si as the light absorption region.
(4) 셀 영역은 실리콘(Si)을 함유하는 것을 특징으로 하는 광기전력 소자.(4) A photovoltaic device, wherein the cell region contains silicon (Si).
(5) 셀 영역은 그룹 3족-비소(As)으로 결합된 화합물을 함유하는 것을 특징으로 하는 광기전력 소자.(5) A photovoltaic device characterized in that the cell region contains a compound bonded with a group III-arsenic (As).
(6) 셀 영역은 그룹 3족-인(P)으로 결합된 화합물을 함유하는 것을 특징으로 하는 광기전력 소자.(6) A photovoltaic device, characterized in that the cell region contains a compound bonded by group III-phosphorus (P).
(7) 셀 영역은 Cu-In-Ga-S(Se)으로 결합된 화합물을 함유하는 것을 특징으로 하는 광기전력 소자.(7) A photovoltaic device, wherein the cell region contains a compound bonded with Cu-In-Ga-S (Se).
(8) 도전성 윈도우는 아연(Zn) 또는 마그네슘(Mg)을 포함하는 산화물로 이루어지는 것을 특징으로 하는 광기전력 소자(예: ZnO, MgZnO, MgO).(8) Photovoltaic devices (eg, ZnO, MgZnO, MgO), wherein the conductive window is made of an oxide containing zinc (Zn) or magnesium (Mg).
(9) 셀 영역은 염료감응형 다이(Dye)와 같은 유기물로 이루어질 수 있다.(9) The cell region may be made of an organic material such as a dye-sensitized die.
본 개시에 따른 하나의 광기전력 소자에 의하면, 기존 유리 기판 및/또는 투광성 전도 산화막(TCO)의 사용에 따른 문제점을 개선할 수 있게 된다.According to one photovoltaic device according to the present disclosure, it is possible to improve the problems caused by the use of the existing glass substrate and / or the transparent conductive oxide film (TCO).
본 개시에 따른 다른 하나의 광기전력 소자에 의하면, 셀 영역을 고온에서 성장할 수 있는 기판(substrate) 내지 기초(base)를 제공할 수 있게 된다.According to another photovoltaic device according to the present disclosure, it is possible to provide a substrate or a base capable of growing a cell region at a high temperature.
본 개시에 따른 또 다른 하나의 광기전력 소자에 의하면, Shunting path, pinholes, local depletion 등의 문제점 해소할 수 있는 거친 표면을 구비한 광기전력 소자를 만들 수 있게 된다.According to another photovoltaic device according to the present disclosure, it is possible to make a photovoltaic device having a rough surface that can solve problems such as shunting paths, pinholes, local depletion, and the like.

Claims (10)

  1. 육방 조밀 격자 구조(Hexagonal Close-Packed Lattice Structure)를 가지는 도전성 윈도우(Conductive Window);로서, 빛이 입사되는 측에 빛을 산란시키는 거친 표면을 가지며, 제1 밴드갭 에너지를 가지는 도전성 윈도우;A conductive window having a hexagonal close-packed lattice structure, the conductive window comprising: a conductive window having a rough surface for scattering light on a side from which light is incident and having a first bandgap energy;
    도전성 윈도우 상에 형성되며, 입사된 빛을 전기 에너지로 전환하고, 제1 밴드갭 에너지보다 작은 밴드갭 에너지를 가지면서 도전성 윈도우를 구성하는 물질과 다른 이종 물질로 된 광 흡수 영역을 가지는 셀 영역; 그리고,A cell region formed on the conductive window and converting incident light into electrical energy, the cell region having a bandgap energy smaller than the first bandgap energy and having a light absorption region made of a heterogeneous material different from the material constituting the conductive window; And,
    셀 영역을 기준으로 도전성 윈도우의 반대 측에서 입사된 빛을 셀 영역으로 반사하는 반사층;을 포함하는 것을 특징으로 하는 광기전력 소자.And a reflective layer reflecting light incident from the opposite side of the conductive window to the cell region with respect to the cell region.
  2. 청구항 1에 있어서,The method according to claim 1,
    제1 밴드갭 에너지는 3eV보다 큰 것을 특징으로 하는 광기전력 소자. The first bandgap energy is greater than 3 eV photovoltaic device, characterized in that.
  3. 청구항 1에 있어서,The method according to claim 1,
    도전성 윈도우는 3족 질화물 반도체로 이루어지는 것을 특징으로 하는 광기전력 소자.A photovoltaic device comprising a conductive window comprising a group III nitride semiconductor.
  4. 청구항 3에 있어서,The method according to claim 3,
    거친 표면은 n-페이스(n-face) GaN에 구비되는 것을 특징으로 하는 광기전력 소자.The photovoltaic device, characterized in that the rough surface is provided in n-face GaN.
  5. 청구항 1에 있어서,The method according to claim 1,
    광 흡수 영역의 밴드갭 에너지는 2eV이하인 것을 특징으로 하는 광기전력 소자.The bandgap energy of the light absorption region is less than 2eV photovoltaic device.
  6. 청구항 4에 있어서,The method according to claim 4,
    광 흡수 영역의 밴드갭 에너지는 2eV이하인 것을 특징으로 하는 광기전력 소자.The bandgap energy of the light absorption region is less than 2eV photovoltaic device.
  7. 청구항 1에 있어서,The method according to claim 1,
    셀 영역은 실리콘(Si)을 함유하는 것을 특징으로 하는 광기전력 소자. The cell region contains silicon (Si).
  8. 청구항 6에 있어서,The method according to claim 6,
    셀 영역은 실리콘(Si)을 함유하는 것을 특징으로 하는 광기전력 소자. The cell region contains silicon (Si).
  9. 청구항 1에 있어서,The method according to claim 1,
    반사층에 결합되는 지지 기판;을 더 포함하는 것을 특징으로 하는 광기전력 소자.A photovoltaic device further comprising; a support substrate coupled to the reflective layer.
  10. 청구항 1에 있어서,The method according to claim 1,
    도전성 윈도우는 아연(Zn) 및 마그네슘(Mg) 중의 적어도 하나를 포함하는 산화물로 이루어지는 것을 특징으로 하는 광기전력 소자.The conductive window is made of an oxide containing at least one of zinc (Zn) and magnesium (Mg).
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