Optical response of a metal-semiconductor field effect transistor in the presence of interface states and interfacial layer at the gate contact

Abstract

A simple analytical model on the electrical characteristics of a metal-semiconductor field effect transistor under optical illumination has been proposed by considering the inherent effects of interface states and interfacial layer at the gate-channel interface. The drain current of the device under optical illumination has been studied by treating optically generated carriers within the framework of a model that concerns arbitrary charge distribution in the channel region. It has been found that for a metal of relatively higher work function acting as the gate contact of the device, the drain current increases with increasing interface state density. An expression for the threshold voltage of the device has been derived and its dependence on the interface state density has been studied. It has been found that both the channel current and threshold voltage of the device increase appreciably under illuminated condition.