GaAs OPFET characteristics considering the effect of gate depletion with modulation due to incident radiation

A realistic analytical model of an ion-implanted GaAs OPFET has been presented. Both the photogeneration and photovoltaic effect and the voltage dependence of the depletion layer widths in the active region have been considered. The threshold voltage decreases in the enhancement device and increases in the depletion device at a particular dose, flux density, and trap center density when both the photovoltaic effect and photogeneration are taken into account compared to the case where the photovoltaic effect is ignored. At higher flux density and trap density, the threshold voltage shows a nonlinear effect at a lower value of the implanted dose, which is mainly due to the recombination term. The drain-source current significantly increases due to the photovoltaic effect because of the widening of the channel region. The device is pinched off at a higher drain-source voltage compared to the photogeneration case only