Implantation damage in amorphous silicon

The effect of irradiation damage on the electrical properties of amorphous Si deposited by the glow-discharge technique has been studied. The irradiations were performed with chemically inactive ion species. Although the results show obvious differences between c-Si and a-Si in their dependence on ion mass and the sample temperature during irradiation, there are nevertheless many similarities and these are particularly apparent in the behaviour of the room temperature electrical conductivity with increasing ion dose. The results suggest that as far as changes in transport properties are concerned the accumulation of radiation damage is similar in a-Si to that in c-Si. A comparison of photoconductivity results with earlier data for implantations with chemically active ions suggests that non-doping configurations of the latter produce additional states in the gap which act as recombination centres. (author)