Investigation of the incident light intensity effect on the internal electric fields of GaAs single junction solar cell using bright electroreflectance spectroscopy

摘要： The incident light intensity (Iex) 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 (Fpn) of the SC was evaluated by analyzing the Franz Keyldesh oscillation (FKO) in the BER spectra. The Iex effect on Fpn was investigated at various incident light intensities from 0.03 to 25 suns. The Fpn decreased gradually with increasing Iex 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 Fpn. Therefore, the Fpn 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 Fpn due to the photovoltaic effect. In addition, the Fpn was examined under light illumination as a function of different DC bias voltages (-0.2 ~ 0.4 V). The Fpn decreased with increasing bias voltage due to the decrease in potential barrier. The Fpn increased with increasing bias voltage due to the decrease in the photogenerated carrier-induced electric field for high Iex.