Improved optical and electrical performances of GaN-based light emitting diodes with nano truncated cone SiO2 passivation layer

A Direct Epitaxial Approach To Achieving Ultrasmall and Ultrabright InGaN Micro Light-Emitting Diodes (μLEDs)

“…III-nitride μLEDs are exclusively fabricated by means of combining a standard photolithography technique and subsequent dry-etching processes on a standard III-nitride LED wafer. − Generally speaking, surface damage will be unavoidably introduced by dry-etching processes, which enhances nonradiative recombination leading to reduction in optical performance. − This issue is minor and can be safely ignored for broad area LEDs with a dimension of >100 μm. However, this issue becomes increasingly severe with decreasing μLED dimension, eventually becoming a major factor and thus leading to severe degradation in optical performance. ,, Although sidewall passivation using dielectric materials can to some degree reduce plasma induced damage to μLEDs during dry-etching processes, the improvement is marginal even if an advanced atomic layer deposition (ALD) technique instead of a standard plasma-enhanced chemical vapor deposition (PECVD) technique is used for surface passivation .…”

Review of a direct epitaxial approach to achieving micro–LEDs

“…[7][8][9][10][11][12] It is well-known that dry-etching processes unavoidably bring substantial damages to the surface and the sidewalls of LEDs, which enhance non-radiative recombination leading to reduction in optical performance. [13][14][15][16][17][18] This may be a minor issue and can be negligible in the case of the fabrication of standard LEDs with a dimension of ≥ 100 µm. However, this issue cannot be ignored anymore when the dimension of µLEDs decreases down to the tens micrometer scale and eventually becomes a major factor which is responsible for severe degradation in optical performance.…”

Enhanced Light Extraction Efficiency by Self-Masking Technology with Carbonized Photoresist for Light-Emitting Diodes

“…Many investigations on surface roughening have been reported [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. To enhance the optical and electrical properties of GaN-based LEDs, Alias et al [ 15 ] used NH 4 OH and H 2 O 2 to roughen N-face GaN substrates, resulting in a uniform distribution of hexagonal pyramidal structures.…”