4 - Time-of-Flight Experiments in Amorphous Chalcogenide Semiconductors

Abstract

A technique has been found very useful as a nondestructive method of investigating transport properties of photoreceptors (these are used in nonimpact printers for electronically processed or stored information). The technique is called Xerographic Time-of-Flight (XTOF) and it can be conveniently employed in parallel with the conventional measurements for photoreceptor characterization. The Time-of-Flight (TOF) principle is based on generating a thin sheet of electron–hole pairs near the surface of the sample—usually a high-resistivity semiconductor with negligible thermal equilibrium-carrier concentration, sandwiched between two electrodes, one of which is semitransparent. Typical information obtained from TOF studies includes carrier mobility and number and depth of traps in the photoreceptor. The interpretation of TOF signals obtained from monolayer photoconductors with non-dispersive transport is relatively simple and straightforward. This causes a significant distortion of the TOF signal, which makes the evaluation much more difficult.