Defect states and carrier capture processes in aSi:H

Abstract

Density-of-states distribution of P-doped aSi:H has been determined using dark and photo-ICTS (Isothermal capacitance transient spectroscopy) techniques for a systematic variation of doping levels. Two bumps are observed in the gap-state profile ; one at 0.5 eV below E c, originating from D −, and the other at 1.1 eV below E c, probably D − intimately coupled with P 4 +. From the energy as well as temperature dependence of the attempt-to-escape frequency of those states, carrier capture processes are discussed in terms of multiphonon emission.