Comparative study of ac losses and mechanisms in amorphous semiconductors.

A comparative study of the real and imaginary loss in III-V amorphous semiconductors and chalcogenide glasses has led to t following two major results. First, no existing mechanism can fully explain all the observed experimental facts; more specifically, although correlated barrier hopping(CBH) of bipolarons between both random and paired defects fits reasonably well the ac conductivity it disagrees with the observed frequency dependence of the capacitance. Second, although the ac loss parameters are very similar for all amorphous semiconductors, only a-SiO2 and a-GeSe2 display a capacitance which obeys the scaling relation: C=Aln(T(omega)(-1)) which suggests a condition mechanism by tunneling relaxation.