Submicron-Gap Photoconductive Switching in Silicon

Abstract

In recent years there has been an increased interest in fast photo conductive switches: switches based on the use of a liant pulse to modulate the resistivity of a semiconducting gap in a high-speed transmission line. To make such a switch fast, one has to restore the gap resistivity to its dark value as soon as possible after the light pulse is turned off. Thus, the ob.iect is to reduce the lifetime of carriers in the gap. In previous work with silicon, this has been achieved by increasing the carrier recombination rate through the use of radiation damaged or amorohous materials [1–2]. This introduction of recombination centers, however, also reduces carrier mobility and thus switch sensitivity. An alternative technique, the one used in this work, is to sweep the carriers out of the gap with an applied electric field.