Geiger-Mode Operation of GaN Avalanche Photodiodes Grown on GaN Substrates

Ultraviolet (UV) GaN p-i-n avalanche photodiodes (APDs) on low dislocation density free-standing GaN substrates were grown and fabricated. The GaN APD showed a stable avalanche multiplication gain in a linear mode, using UV illumination. In Geiger-mode operation at room temperature with gated quenching, no after-pulsing effect was observed up to 100 kHz. The single-photon detection efficiency and dark-count probability were measured to be ${\sim}$1% and ${\sim} 3\times 10^{- 2}$ at 265 nm, respectively.