A study on the effects of amphoteric defect concentration on the characteristics parameters of In x Ga1−x N thin-film solar cells

Abstract

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 lm. 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.

Light Trapping Induced High Short-Circuit Current Density in III-Nitride Nanorods/Si (111) Heterojunction Solar Cells

“…However, the issues of impurities and non-radiative recombination become increasingly significant under low-temperature InGaN thin film growth conditions [28][29][30]. The significant stacking faults and dislocation densities due to lattice mismatch lead to the decrease in carrier diffusion length and the limitation of solar cell PCE [31][32][33][34]. Therefore, numerous challenges remain for the realization of the potential capabilities of high-efficiency III-nitride photovoltaic devices.…”