Current Applied Physics, Vol.20, No.1, 145-149, 2020
Investigation of the incident light intensity effect on the internal electric fields of GaAs single junction solar cell using bright electroreflectance spectroscopy
The incident light intensity (I-ex) effects on a GaAs single junction solar cell (SC) was investigated using bright electroreflectance spectroscopy (BER) and current-voltage (J-V) measurements at room temperature. The p-n junction electric field (F-pn) of the SC was evaluated by analyzing the Franz Keyldesh oscillation (FKO) in the BER spectra. The I-ex effect on F-pn was investigated at various incident light intensities from 0.03 to 25 suns. The F-pn decreased gradually with increasing I-ex due to the photovoltaic effect. For the forward bias voltage, some part of the electrons and holes drifted to the p and n sides, respectively, and produced the induced electric field in the same direction of the F-pn. Therefore, the F-pn increased up to 2.5 suns. At more than 2.5 suns, most of the electrons and holes moved to the n and p sides and decreased the F-pn due to the photovoltaic effect. In addition, the F-pn was examined under light illumination as a function of different DC bias voltages (- 0.2-0.4 V). The F-pn decreased with increasing bias voltage due to the decrease in potential barrier. The F-pn increased with increasing bias voltage due to the decrease in the photogenerated carrier-induced electric field for high I-ex.