Influence of electron and proton irradiation on the electronic properties of microcrystalline silicon

We report and detail changes in the electronic properties of microcrystalline silicon (muc-Si) films after 1-MeV electron and 100-MeV proton irradiation. We studied these irradiation effects on undoped muc-Si samples from plasma-enhanced chemical vapour deposition (PECVD) and hot-wire chemical vapour deposition (HWCVD). The samples under investigation also cover a doping series of HWCVD muc-Si samples with a room-temperature dark conductivity range between 10(-7) S/cm and a few S/cm for both n-type and p-type doping in the as-deposited state. Experimental methods applied before and after irradiation include dark conductivity, photoconductivity for the majority carriers and steady-state photocarrier grating for the minority carriers. Application of modulated photocurrent and constant photocurrent methods provide information on changes in the density of states. Annealing effects on the electronic properties are reported for sample storage at room temperature. (C) 2002 Elsevier Science B.V. All rights reserved.