渐变带隙Cd_(1-x)Zn_xTe太阳电池光电转换效率的数值模拟

Numerical Simulation of Photoelectric Conversion Efficiency of Graded Band-gap Cd_(1-x)Zn_xTe Solar Cell

Cd_(1-x)Zn_xTe是直接带隙半导体材料,其禁带宽度随x值的变化在1.45eV～2.26eV间连续可调。将具有渐变带隙结构的材料作为太阳电池的光吸收层,可以在近背表面的薄层内产生一个准电场。该电场不仅能将俄歇复合发生的位置有效局域化,而且还可降低由表面复合引起的载流子损耗,增强光生载流子的收集效率,进而提高电池的光电转换效率。用渐变带隙Cd_(1-x)Zn_xTe多晶薄膜替代了传统CdTe薄膜太阳电池中的均匀相CdTe光吸收层,并用AMPS软件模拟分析了渐变带隙Cd_(1-x)Zn_xTe太阳电池的光电响应特性。经计算,该电池在理想情况下(无界面态、有背面场,正背面反射率分别为0和1)的光电转换效率高达41%。

Cd_（1-x）Zn_xTe is a direct band-gap semiconductor and its band-gap can be tailored in the range of 1.5eV～2.26eV.By using a material containig a graded band-gap structure as the optical absorption layer of a solar cell,a quasi electric field can be generated in a thin layer near the back surface of the solar cell.The electric field not only can effectively localize the position in which the Auger recombination occured,but also can reduce the carrier loss due to the surface recombination,improve the collection efficiency of photo-generated carriers and hence improve the photoelectric conversion effciency of the cell.The Cd_（1-x）Zn_xTe polycrystalline thin film with graded band-gap profile is used to replace the uniform CdTe thin film in a conventional CdTe solar cell.Then,the AMPS software is used to analyze the photoelectric behavior of the solar cell.The calculation result shows that the cell has its photoelectric efficiency up to 41%in the ideal condition.