Relaxation of electrical properties of stabilized amorphous selenium based photoconductors

We have examined the relaxation of the electrical properties of vacuum deposited films of stabilized amorphous selenium (a-Se:0.2%As) as the films relaxed from immediately after deposition, as well as immediately after annealing above T-g. Time-of-flight (TOF) and interrupted field time-of-flight (IFTOF) transient photoconductivity measurements were carried out to measure the electron range (mu(e)tau(e)) and hole range (mu(h)tau(h)) as a function of 'aging' time at room temperature. We found that although the mobility for both electrons and holes does relax over time, the change in mobility is less significant than the change in the lifetime. We also found that both the electron and hole lifetimes relax in a stretched exponential manner with approximately the same structural relaxation time. (C) 2007 Elsevier B.V. All rights reserved.