Study of Band Tails in a-SiGe:H Alloys from Time of Flight and Thermally Stimulated Current Experiments

Abstract

ABSTRACTThermally stimulated current (TSC) and Time of flight (TOF) experiments have been performed on the same set of Pt/a-SiGe:H Schottky diodes in order to compare the band tail characteristics obtained from the two methods. For the silicon rich alloys, good agreement is found in the values of the band tail width. However, the values of the attempt-to-escape frequencies obtained from TSC are typically orders of magnitude smaller than those obtained from TOF. To analyse the origin of this discrepancy we propose another kind of TSC experiment denoted Pulsed TSC: short voltage pulses are applied to the sample while it is heated and the resulting current is monitored. Preliminary results are presented and discussed .