Research Of The Structure Design And Polarization Effect Of InGaN Solar Cells

InGaN solar cells have higher conversion efficiency than traditional Si based solar cells. However, efficiency of experimental InGaN solar cell is lower than expected efficiency. There are still several problems, such as the design structure of InGaN solar cells, the quality of InGaN materials, need to be discussed and solved. In addition, InGaN materials exhibit a strong polarization, which plays an important role in its fabrication and usage. Thus, the researches of structure design and polarization effect are important for the implications of InGaN solar cells. The main work are listed as follows,The p-In0.65Ga0.35N/n-In0.65Ga0.35 N solar cells with band tail defects were simulated. The simulated results show that the increase of reverse saturation current and the decrease of Voc are mainly responsible for the decrease of the efficiency. When the capture cross section is 10-14cm-2, the efficiency decreases sharply from24.12% to 12.76%.The performance of p-GaN/i-InxGa1-xN/n-GaN solar cells with different In content was simulated. It is found that the optimum efficiency of p-GaN/i-InxGa1-xN/n-GaN solar cell is 8.90% when the In content is 0.26. The p-GaN/i-In0.26Ga0.74N/n-GaN solar cells with band tail defects were simulated. The simulated results show the efficiency decreases sharply from 8.90% to 7.19% when the capture cross section is 10-14cm-2.The polarization effect of InGaN solar cells was simulated by AMPS-1D software. Firstly, properties of GaN/InGaN hetero-structures were studied and the relationship between polarization charge density and In content in the InGaN barrier had been discussed. The properties p-GaN/i-In0.26Ga0.74N/n-GaN double hetero-structures were studied. The simulation results show that polarization charges will seriously degrade the solar cell performance. When the screening coefficient is 0.6, the efficiency decreases sharply from 8.90% to 2.13%.