CAJ | 학술논문

基于GaSb薄膜热光伏器件是降低热光伏系统成本的有效途径之一，本文主要针对GaSb/CdS薄膜热光伏器件结构进行理论分析.采用AFORS-HET软件进行模拟仿真，分析GaSb和CdS两种材料各自的缺陷态密度、界面态对电池性能的影响.根据软件模拟可以得知，吸收层GaSb的缺陷态密度以及GaSb与CdS之间的界面态密度是影响电池性能的重要因素.当GaSb缺陷态增加时，主要影响电池的填充因子，电池效率明显下降.而作为窗口层的CdS缺陷态密度对电池性能影响不明显，当CdS缺陷态密度上升4个数量级时，电池效率仅下降0.11%.
기우GaSb박막열광복기건시강저열광복계통성본적유효도경지일，본문주요침대GaSb/CdS박막열광복기건결구진행이론분석.채용AFORS-HET연건진행모의방진，분석GaSb화CdS량충재료각자적결함태밀도、계면태대전지성능적영향.근거연건모의가이득지，흡수층GaSb적결함태밀도이급GaSb여CdS지간적계면태밀도시영향전지성능적중요인소.당GaSb결함태증가시，주요영향전지적전충인자，전지효솔명현하강.이작위창구층적CdS결함태밀도대전지성능영향불명현，당CdS결함태밀도상승4개수량급시，전지효솔부하강0.11%.
Enthusiasm in the research of thermo-photovoltaic (TPV) cells has been aroused because the low bandwidth semi-conductors of III-V family are coming into use. GaSb, as a member of III-V family, has many merits such as high absorption coeffcient, and low band gap of 0.725 eV at 300 K etc.. At present thermo-photovoltaic cells are usually based on GaSb wafer, and it can be manufactured by the vertical Bridgeman method. Thermo-photovoltaic cell based on GaSb films is one of the effective ways to reduce the cost of the thermo-photovoltaic system. GaSb polycrystalline films can be grown by physical vapor deposition (PVD) which has advantages in using fewer materials and energy, and also in doing little harm to the environment. Because of residual acceptor defects VGaGaSb, GaSb thin film is usually of p-type semiconductor. So we should find n-type semiconductor material to form pn junction. We choose CdS as the emission layer of a cell structure. CdS belongs to n-type semiconductor with a narrow band gap of 2.4 eV and high light transmissivity. CdS thin film grown by chemical bath deposition (CBD) has passivation properties for GaSb. CdS layers can remove native oxides from GaSb surface and reduce the surface recombination velocity of GaSb. This paper focuses on theoretical analysis of GaSb/CdS thin film photovoltaic structure. By way of AFORS-HET simulation, we analyze the defect state density and interface density in GaSb and CdS, and their effects on cell performance. According to the simulation, the defect density in GaSb absorption layer is the very important factors that affect cell performance. When GaSb defect increases, the major factor to affect the cell is the fill factor that leads to low effciency. On condition that there exists high GaSb defect density, the thickness of GaSb should be kept at 1000 nm. GaSb with a thickness above 1000 nm can bring about a high recombination rate, which reduces the effciency of the cell. As an emission layer, the defect density in CdS should not affect the cell performance obviously. When the increase of CdS defect density is of four orders of magnitude, the cell effciency is only decreased by 0.11%. In order to demonstrate the interface between GaSb and CdS, we use an inversion layer n-GaSb according to the passivation properties of CdS thin film grown on GaSb. When the defect density of inversion layer increases, the effciency of the cell will decrease rapidly. And the GaSb/CdS structure will act as a resistance when the defect density in the inversion layer reaches 1020 cm?3. So the defect density in GaSb layer and the interface is the very factor to affect thermo-photovoltaic performance.