Geiger mode simulation of GaN homojunction avalanche photodetectors

We investigate the Geiger mode operation of wurtzite GaN-based homojunction avalanche photodiodes (APDs) via full-band ensemble Monte Carlo charge transport simulation. Critical design parameters for photon counting applications are identified, and their influence on single photon detection efficiency (SPDE) is quantified. Simulations demonstrate simultaneous reduction in breakdown field strength and growth in SPDE with increasing active region thickness. We also report a significant increase in avalanche growth rate with reduction in active region thickness, and relate for the first time the characteristic time scale to the product of avalanche coefficients and saturated drift velocities. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)