The temperature dependence of the time-averaged drift mobility in As 2S 3 glass derived from PA measurements

Abstract

The temperature dependence of the bimolecular recombination rate coefficient ( b) and the time-averaged drift mobility in As 2S 3 glass was studied in the range 77–330 K on the basis of steady-state photoinduced absorption (PA) measurements. PA measurements have been carried out on glass samples in the form of optical fibres. The steady-state PA coefficient varies approximately as the square root of the excitation light intensity, indicating a bimolecular mechanism for the recombination of excess carriers. In most disordered semiconductors carrier transport is diffusion-limited and taking into account that for chalcogenide glasses the electron drift mobility μ n≪ μ p the hole drift mobility, the latter was derived from μ p=( εε 0/ e) b. The time-averaged mobility, μ p, was found to be thermally activated at the higher temperatures with activation energy ∼0.9 eV, and with μ p∼10 −10 cm 2/Vs at 300 K, but almost temperature independent below approximately 130 K.