当前太阳能电池存在的一个普遍缺点是转换效率偏低，尤其是对于卫星、宇宙飞船等太空中的应用，由于场地面积非常有限，所以采用高转换效率的太阳能电池带来的好处是不言而喻的。目前高转换效率太阳能电池的研究热点是多结太阳能电池，也叫串联式太阳能电池，InGaN通过改变In组份可以实现禁带宽度从0.7 eV到3.4 eV的连续变化，这点非常适合制作多结太阳能电池，而且有实验表明InGaN具有比GaAs更强的抗辐照特性，更适合太空应用。 本文首先讲了太阳能电池的一些基础知识，然后对GaN和InGaN的材料参数及InGaN多结太阳能电池结构进行了深入的研究。本文的研究成果主要有：1)关于GaN和InGaN材料折射率参数n和消光系数k的模型，本文通过学习和改进以往模型，建立了与实验数据更相符的n和k的模型。同时，本文重新拟合了GaN和InGaN材料电子低场迁移率模型中的参数，使其与实验结果更接近。2）本文分别建立了InGaN单结、双结和三结太阳能电池结构模型，并利用Silvaco Atlas软件对其进行了仿真及结果分析，在AM1.5太阳光谱1倍光强下，分别实现了24.6%、32%和36%的高转换效率，同时对各结构太阳能电池进行聚光下仿真，转换效率都有明显提升，最后分析了少子寿命的影响，得出适当提高少子寿命会使转换效率有较明显提升的结论。

At present, a general disadvantage of solar cell is lower conversion efficiency, especially for satellites, spacecraft and other space applications. Due to the limited area in space applications, using a high conversion efficiency solar cell is of great benefit. Now, the focused research of high efficiency solar cell is multi-junction solar cell, another name of which is tandem solar cell. The direct band gap of the InGaN alloy system extends continuously from 0.7 eV to 3.4 eV, which is very suitable to fabricate a multi-junction solar cell. Some experiments show that InGaN is able to withstand a greater amount of radiation than GaAs does. So the InGaN alloy is more suitable than GaAs for space applications. At the beginning of this thesis, some basic knowledge of solar cell is introduced. After that, a depth research is done about the material parameter of GaN and InGaN. Another depth research is the structure of InGaN multi-junction solar cell. The major achievements are listed.I. This thesis refits the models of the refractive index (n) and the extinction coefficient (k) of GaN and InGaN, making them more consistent with experimental result. This thesis also refits the parameters of the low field electron mobility model of GaN and InGaN, and getting an experimentally based model. II. This thesis build models of single junction, double junction, and triple junction solar cells. Silvaco Atlas was used to simulate these models. The conversion efficiencies of these solar cells at AM1.5 (1sun) are 24.6%, 32%, 36% respectively. When concentrating the sun, the conversion efficiency is increased significantly. At last, through the analysis of minority carrier lifetime, this thesis get a result that an appropriate increase in minority carrier lifetime can increase the conversion efficiency of a solar cell significantly.