Charge transport in amorphous xerographic photoreceptor films of chlorine-doped Se_0.995As_0.005

Time-of-flight drift mobility experiments have been carried out on evaporated films of amorphous (a-)Se_0.995As_0.005 with chlorine as an additive up to approximately 70 at.ppm; drift mobility has been measured as a function of temperature at various applied fields. It is shown that shallow hole traps at approximately 0.45 eV in a-Se, introduced by Cl, are diminished by addition of 0.5% As and that the hole transport in this system is similar to that in pure a-Se. Electron transport, which is trap-limited in Cl-doped a-Se, is restored by light alloying with As. The mobility activation energy increases sharply with addition of even a fraction of a per cent of As. Doping a-Se_0.995As_0.005 with Cl leaves the electron transport relatively unaffected. The experimental data have been critically analysed within the framework of trap-controlled transport mechanisms.