Photoconductivity of Selenium and Sulphur Doped a-Si:H thin Films

Authors: SANJEEV KUMAR SHARMA, HIMANSHU GUPTA, RAJENDRA KUMAR, RAM MOHAN MEHRA

Abstract: This paper presents a study of photoconductivity of S- and Se-doped a-Si:H as a function of composition and temperature. Temperature dependence of photoconductivity of the films was measured under the illumination of white light at 100~mW/cm^2. The room temperature photoconductivity for the same doping concentration of 10^{-4} (to develop H_2Se/SiH_4 and H_2S/SiH_4) is found to be higher in Se-doped -- than S-doped -- a-Si:H film due to a low defect density. From the measurement of intensity dependence of photoconductivity, it is found that the addition of Se and S changes the recombination mechanism from monomolecular, for low-doped films, to bimolecular at higher levels of doping of Se and S.

Keywords: Se, S, a-Si:H, Photoconductivity, recombination mechanism.

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