Abstract
Capacitance, conductance, and photoinduced current measurements have been made on Pd-Si metal-insulator-semiconductor diodes to define the mechanism by which these devices sense hydrogen. The results have been used to construct a model which is capable of describing the major features of the response of these diodes to hydrogen. The current flow is found to be majority carrier dominated, through interface states at the SiO2-Si interface. Changes in current under reverse bias upon exposure to hydrogen result from lowering of both the Schottky barrier and the oxide barrier height but not from changes in the interface density of states.