Dielectric Spectroscopy of Semiconductors

Our understanding of the frequency dependence of transport in a two- dimensional electron gas 2-DEG as seen in a nearly-cut-off Field-Effect Transistor FET is now reasonably complete, earlier difficulties having been due to confusing experimental artifacts. The result in a confirmation of our prediction that 2-DEG should show strong Low-Frequency Dispersion LFD, which has some fundamental significance. We are expanding our studies to the investigation of the decay of photo-voltages in p-n junctions on high- resistivity silicon, the dielectric spectra of which were described in the 3rd Progress Report. We believe that the results will be of some interest for the better understanding of the recombination processes in these devices. The new many-body theory of the fractional power-law time-dependence of trapping generation processes in deep levels in space charge regions of p-n junctions and Schottky barriers has now been accepted by Solid State Electronics. This theory departs radically from previously accepted interpretations which predict near exponential decay, while our experimental evidence shows that this is only a limiting case of a much more general form of dependence.