On the Scope of GaN-Based Avalanche Photodiodes for Various Ultraviolet-Based Applications

We present a review of GaN avalanche photodiodes. GaN-based avalanche photodiodes are of emerging interest to the device community. The review covers various important aspects of the device such as the design space, substrate choice, edge termination efficacy, and last, but not least, the physics behind the avalanche breakdown in GaN. The study comprehends the reported impact ionization coefficients and how they may affect the device performances. Finally various reported GaN APDs are summarized and compared. We conclude that hole-initiated GaN APDs on free-standing GaN substrates can offer unprecedented advantages as ultraviolet light detectors, due to their ultra-high responsivity and low dark current.

Automated summary

This review presents an overview of GaN avalanche photodiodes (APDs). GaN-based APDs have gained interest from the device community. The review discusses important aspects of the device, including the design space, substrate choice, edge termination efficacy, and the physics behind avalanche breakdown in GaN. The study also covers reported impact ionization coefficients and their impact on device performance. Various reported GaN APDs are summarized and compared. The conclusion is that hole-initiated GaN APDs on free-standing GaN substrates offer advantages as ultraviolet light detectors, with their ultra-high responsivity and low dark current.