The temperature dependence of the time-averaged drift mobility in As2S3 glass derived from PA measurements

The temperature dependence of the bimolecular recombination rate coefficient (b) and the time-averaged drift mobility in As2S3 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 mu(p), << mu(p) the hole drift mobility, the latter was derived from mu(p) = (EE0/e)b. The time-averaged mobility, mu(p), was found to be thermally activated at the higher temperatures with activation energy similar to 0.9 eV, and with mu(p) similar to 10(-10) cm(2)/Vs at 300 K, but almost temperature independent below approximately 130 K. (C) 1998 Elsevier Science B.V. All rights reserved.