Determination of the D 0/− level in amorphous Si,Ge:H(F) by time-of-flight charge collection

Abstract
We describe and demonstrate a new method for determining the density of states of the doubly occupied D0/ level in amorphous hydrogenated silicon and its alloys. The total charge collected during an electron time‐of‐flight measurement is determined as a function of T. T determines the energy E from which electrons are emitted during the measurement. Variation of T (and E) probes the local density of states. We present results for hydrogenated amorphous silicon before and after light soaking, and for amorphous silicon‐germanium (a‐Si,Ge:H,F) alloys.