Dynamic behavior of photocarriers in a GaAs metal-semiconductor-metal photodetector with sub-half-micron electrode pattern

Abstract

Simulation results of the temporal evolution of photocurrent in an interdigitated GaAs metal-semiconductor-metal photodetector are presented. The dependence of response time on the distance between fingers (0.1 and 0.25 μm) is investigated. The solutions of the time-dependent Schrödinger equation and ensemble Monte Carlo calculations are employed. For a device with 0.1 μm finger spacing, the response time of an intrinsic detector is less than 2 ps, with hole current decay being the major limiting factor. The role of parasitics is shown to significantly increase the simulated response time.