InGaN Multi-junction Solar Cell Simulation

At present, a general disadvantage of solar cell is lower conversion efficiency,especially for satellites, spacecraft and other space applications. Due to the limited areain 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 alloysystem extends continuously from0.7eV to3.4eV, which is very suitable to fabricate amulti-junction solar cell. Some experiments show that InGaN is able to withstand agreater amount of radiation than GaAs does. So the InGaN alloy is more suitable thanGaAs 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 majorachievements are listed.I. This thesis refits the models of the refractive index (n) and the extinctioncoefficient (k) of GaN and InGaN, making them more consistent with experimentalresult. This thesis also refits the parameters of the low field electron mobility model ofGaN and InGaN, and getting an experimentally based model.II. This thesis build models of single junction, double junction, and triple junctionsolar cells. Silvaco Atlas was used to simulate these models. The conversion efficienciesof these solar cells at AM1.5(1sun) are24.6%,32%,36%respectively. Whenconcentrating the sun, the conversion efficiency is increased significantly. At last,through the analysis of minority carrier lifetime, this thesis get a result that anappropriate increase in minority carrier lifetime can increase the conversion efficiencyof a solar cell significantly.