The electron drift mobility in arsenic–selenium glasses

The drift mobility of electron carriers in vitreous selenium and in arsenic–selenium glasses containing up to 8% As, has been measured over a range of temperature and electric field. The low-field data for selenium itself are in agreement with those in the literature, whilst at higher fields the mobility is found to increase in a manner similar to that observed for hole carriers in selenium, and for the mobility and conductivity in a number of other disordered semiconductors. The electron mobility in arsenic-containing glasses is also field-dependent, whilst the magnitude of the mobility decreases with increasing arsenic concentration. How-ever, the effect of arsenic addition is found to be smaller than has been reported in the case of evaporated amorphous films. A model is advanced to account for the behaviour in terms of current theories of the disordered state.