A numerical simulation of high speed GaAs photodetectors

The authors consider the theoretical understanding and modelling of photodiodes. Although the basic principals of optical detection are understood, the device response and characteristics when illuminated with ultra short pulses of the order of pico-seconds can only be theoretically determined by numerical simulation. This type of model is know as the drift-diffusion model and solves the classical transport equations for electrons and holes. A similar approach was used by Peterson (see IEEE J. Quantum Electron., vol.QE-23, no.7, p.1185-92, 1987) to model Si interdigitated photoconductors,which successfully predicted the device response. The authors extend this work by the inclusion of the Schottky barrier in the model and the use of field dependent carrier transport properties