Evidence of optically induced degradation in gallium nitride optoelectronic devices

Abstract

We provide experimental evidence that gallium-nitride-based optoelectronic devices can be affected by a photon-driven degradation mechanism unrelated to catastrophic optical damage. Any role of current in such degradation is excluded by stress tests under laser irradiation in the opencircuit configuration; any role of temperature is ruled out by additional thermal tests, showing a different degradation mode. Given the high bond strength of GaN, lattice-damage-related degradation is unlikely. A possible cause, supported by the PL spectra, is the dehydrogenation of gallium vacancies, which causes an increase in the number of optically active defects and requires a removal energy lower than the photon energy.

Defects and Reliability of GaN‐Based LEDs: Review and Perspectives

“…De Santi et al investigated this topic on InGaN–GaN multiple quantum wells (MQWs) 1 × 1 mm 2 photodetectors, with 30 QWs. [ 109 ] These devices, that have a LED‐like structure, can be used in wireless power transfer systems and must be able to withstand optical intensities up to hundreds of W/cm 2 . The authors stressed the devices under open‐circuit conditions at 361 W cm −2 for 486 h with a 405 nm continuous wave laser diode.…”

“…De Santi et al investigated this topic on InGaN-GaN multiple quantum wells (MQWs) 1 Â 1 mm 2 photodetectors, with 30 QWs. [109] These devices, that have a LED-like structure, can be used in wireless power transfer systems and must be able to with the model proposed in the study by Ruschel et al [99] The devices under test were commercial UV-B LEDs with nominal current of 350 mA, stressed at 250 mA at room temperature for 300 h. Reproduced with permission. [24] Copyright 2020, The Optical Society.…”

“…[65,119,120] In fact, diffusion in one dimension is explained by Fick's second law. The model to explain the relation between the local concentration of the diffusing species N diff , position, and time, assuming that the concentration at the [109] Copyright 2018, The Japan Society of Applied Physics.…”

“…a) Photoluminescence of unstressed device and b) 486 h stressed device. Reproduced with permission [109]. Copyright 2018, The Japan Society of Applied Physics.…”

Lifetime Prediction of Current-and Temperature-Induced Degradation in Silicone-Encapsulated 365 nm High-Power Light-Emitting Diodes

“…d.) Photo-induced effects: Results presented by De Santi et al [62] demonstrated the formation of point defects in irradiated InGaN LEDs using a 405 nm laser and an irradiance of 361 W cm −2 . Similar results were reported by Caria et al [63] in open-circuit conditions.…”