Negative dielectric relaxation of hot electrons in CdTe

A direct measurement of negative dielectric relaxation in CdTe at room temperature is presented at electric fields where electrons exhibit negative differential mobility. Data have been obtained with the time-of-flight technique, which is suitable to investigate electron diffusion process and space charge effects by means of an analysis of the time and space evolution of an electron charge layer drifting in a semiconductor material exhibiting either positive or negative differential mobility.