科研之友
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摘要
Group III nitride semiconductors can partly cover the solar spectrum from ultraviolet to infrared spectra due to their ability to vary their band gap. These semiconductors have a substantial potential to develop ultrahigh efficiency solar cells. However, defects have a profound effect on their power conversion efficiency. Since defects lead to dramatic changes in electronic and optoelectronic properties, controlling process to get acceptable defects density in solar cells is a noteworthy parameter in technological and device applications. This paper indicates a numerical simulation study to optimize the p-i-n InGaN homojunction solar cells by investigation of defect density in the whole cell structure. In this study, we assumed that the p-region and n-region thicknesses are 100 and 150 nm, respectively, and the optimized value of cell thickness is 1.3 mu m. Similarly, we chose amphoteric defect density from 10(15) to 10(19) cm(-3), and then the effects of defects density on characteristic parameters of cell have been studied. Based on our results, when the amphoteric defect concentration is below the 10 15 cm-3, constant value for FF values in all layers was obtained. Therefore, cell efficiency remains the same in lower amphoteric defect density where all FF, V-OC and J(SC) are constant. By increasing the amphoteric defect density from 10(15) cm(-3), the cell efficiency falls down dramatically from 20 to about 1 % at 10(19) cm(-3). In our simulated structure, the cell efficiency parameter decreases with increasing the defects density until it reaches the 10(15) cm(-3). Above this value, no change in the parameters was observed. Our results revealed that the high defect density range 10(15)-10(19) cm(-3) may be an equally significant cause of performance loss.
- 出版日期2016-7
