MODELING OF P-I-N PHOTODIODES UNDER HIGH ILLUMINATION CONDITIONS

The response of a p-i-n photodetector made from gallium arsenide to bo th steady-state and transient illumination has been modelled. Both an ensemble Monte-Carlo model and a drift-diffusion model were used, the latter with the choice of two different mobility models. The effects o f high intensity steady-state illumination on the field and carrier di stributions in the photodetector were calculated, and a comparative st udy of the models made. The transient response to pulsed illumination has also been calculated and the different results obtained from the m odels explained. The effect of high illumination on the response speed of the detector has been demonstrated. In addition, an expression for obtaining the photocurrent from the Monte-Carlo simulation, with much reduced statistical noise over the conventional estimate, has been de rived and successfully tested. (C) 1997 by John Wiley & Sons, Ltd.