GaN ultraviolet avalanche photodiodes fabricated on free‐standing bulk GaN substrates

Abstract

We report high‐performance MOCVD‐grown GaN ultraviolet (UV) p‐i‐n avalanche photodiodes (APD) on bulk GaN substrates. The fabricated APD achieved avalanche gain of > 3 × 104 and low leakage current density (<10–7 A/cm2) at voltages below 50% of the device avalanche breakdown voltage. To the best of our knowledge, this is the highest linear gain reported to date among III‐N‐based UV APDs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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

“…Large defect density, as well as the etching-induced damages, contributed significantly to the high dark current density, which is in the range of 10 -4 to 1 A/cm 2 (Verghese et al, 1998;Carrano et al, 2000;Cicek et al, 2010;Sun et al, 2010). With the introduction of GaN-on-GaN APDs, as shown in Figure 9B, dark current density of less than 10 -4 A/cm 2 could be realized, along with a gain of 10 4 (Limb et al, 2006;Shen et al, 2007;Yoo et al, 2007;Zhang et al, 2008;Zhang et al, 2009).…”

Comparison of ultraviolet APDs grown on free-standing GaN and sapphire substrates

“…The same area FS-GaN-APD, under front-illumination, achieved a maximum gain of ~14 000 shown in Figure 3 This gain is comparable to other works. 18 In Figure 4 (b), the gain of both sapp-APDs and FS-GaN-APDs is plotted as a function of area. The gain of FS-GaN-APDs decreases from ~14 000 to ~150 as the diode area increases from 225 to 7225 µm 2 .…”

Growth and fabrication of high-performance GaN-based ultraviolet avalanche photodiodes

“…Optical gains 410 5 have been measured under photocurrent-limited operation for other similar GaN APDs operating at higher reverse currents. [28] The responsivity vs.…”