The influence of deposition temperature and annealing temperature on the optoelectronic properties of hydrogenated amorphous silicon films

Abstract

The relaxation of pulse-induced mobile charge carriers in a-Si:H films is followed by transient photoconductivity measurements in the microwave frequency range (time resolved microwave conductivity measurements). It is shown that a-Si:H films deposited at substrate temperatures lower than 150 °C are characterized by a lower electron drift mobility and a higher deep trap concentration for electrons than a-Si:H films deposited at 250 °C, where films deposited at 150 °C have only a lower drift mobility. Annealing of a film deposited at 30 °C leads to a higher drift mobility and a lower deep trap concentration with increasing annealing temperature. However, the (opto)electronic properties of the annealed films are still inferior to those of films deposited at the annealing temperature.