Effect of substrate illumination on the characteristics of an ion implanted GaAs OPFET

An analytical model of an ion-implanted GaAs MESFET has been developed considering the illumination from the substrate. The ion-implanted profile of the channel region is represented by Pearson IV distribution. Modulation of the channel opening due to the internal photovoltage has been considered. The I-V characteristics, the photocurrent, the internal photovoltage and the transconductance of the device have been calculated and discussed. The substrate doping concentration is found to affect the overall drain-source current under illumination, which indicates a significant substrate effect on the device characteristics. The illumination also enhances the current of the MESFET compared to that in the dark. The I-V characteristics, transfer characteristics and the ratio of drain currents under illumination and in the dark have been plotted and discussed