Some Travelling-wave Interactions in Semiconductors Theory and Design Considerations†

Abstract

A general analysis of the interaction of a slow wave with a drifting stream of carriers is presented, The slow wave has an associated electric field, and may be electromagnetic or acousto-electric in character. The effects of both collision and diffusion are included in the analysis. The vacuum travelling-wave tube and the acoustic semiconductor amplifier emerge as special cases. The results are used to evaluate the feasibility of obtaining net gain from the interaction of drifting carriers in a semiconductor with the electromagnetic wave guided by an external structure. The conditions which provide the best hope of success are identified. The required physical materials constants arc only partially known, but using the best available estimates the theory suggests that substantial gains should be attainable.