Negative differential capacitance of amorphous silicon films

Abstract

The surface voltage V of undoped amorphous silicon films has been measured as a function of the applied surface charge Q as in electrophotographic photoreceptor applications. It is found that the Q-V characteristic is nearly linear at low charge, but that the voltage saturates and eventually decreases with continued charging. This phenomenon of negative differential capacitance is explained by considering a field-dependent carrier generation and subsequent carrier transport in an amorphous solid. It is shown that the observed results arise from the buildup of space charge when the electron and the hole μτ products are sufficiently different.

Sb-mediated Ge quantum dots in Ti–oxide–Si diode: negative differential capacitance

“…It has found interesting applications, such as in a metal–semiconductor field-effect transistor [19]. So far, NDC has been reported in amorphous Si [20] and in n-GaN–p-Si heterojunctions [21]. If a SiGe-based device could be developed showing the NDC effect, it will widen even more the already vast technological application spectrum of the SiGe system.…”