采用第一性原理广义梯度近似+U(GGA+U)方法计算了纤锌矿结构 Zn1–xMgxO(ZMO)(0≤x≤0.25)合金的能带结构.计算表明: 随着Mg组分增加, ZMO化合物的导带底及费米能级均向真空能级方向移动, 带隙增宽.基于理论计算得到ZMO的能带结构参数, 使用SCAPS软件对ZMO作窗口层的CdTe薄膜太阳电池的性能进行了仿真模拟, 并将研究结果与CdS作窗口层的CdTe太阳电池的性能进行了比较.结果表明: Mg在ZMO中的含量0≤x≤0.125时, ZMO/CdTe太阳电池具有比CdS/CdTe太阳电池更高的开路电压和短路电流密度; ZMO的导带底高出CdTe导带底约0.13 eV时, CdTe薄膜太阳电池的转换效率最高, 达到18.29%.这些结果为高效率碲化镉薄膜太阳电池的结构设计和器件制备提供了理论指导.%In this paper, the band structure of Zn1–xMgxO(ZMO) alloy with different Mg compositions by using first-principles calculations with GGA+U method was studied. The calculation results show that position of con-duction band offset and Fermi level of Zn1–xMgxO move towards the vacuum level while the band gap becomes wider with the increasing Mg concentration. Based on theoretical calculation results of ZMO, ZMO/CdTe, CdS/CdTe solar cells were modeled using SCAPS software and its device performances were simulated and ana-lyzed in detail. The results indicate that the conversion efficiency of CdTe solar cell with ZMO is higher than that of solar cell with CdS due to the high open circuit voltage and short circuit current density when x in Zn1–xMgxO is in the range of 0-0.125. Efficiency of CdTe solar cells with ZMO reaches 18.29% because the recombination de-creases obviously resulting from appropriate conduction band offset about 0.13 eV at ZMO/CdTe interface. These data provide a theoretical guidance for design and fabrication of high efficiency CdTe solar cells.
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