A GaN-based light-emitting diode (LED) with an air-buffer layer and textured sidewalls is fabricated and investigated. After the deposition of a 1-μm silicon dioxide (SiO2) passivation layer on the whole device region except for the sidewall, a hot KOH etching solution is used to develop the desired textured sidewall. Many sidewalls with triangular-like shape are produced along the specific direction of 〈 1 over(1, ̄) 0 0 〉, where photons introduced within multiple-quantum-well (MQW) exhibit more opportunities to scatter into the air. Based on the lateral etching, many triangular-shaped cones are formed on the patterned sapphire substrate (PSS). The device sidewall inclines with a 24° angle which results in an improved reemission of photons in the vertical/lateral direction. At 20 mA, as compared with the LED without KOH treatment, the studied device exhibits improved output power by 11.7% without deteriorating its electrical characteristics. This phenomenon can be attributed to the enhanced output light from vertical and lateral directions due to the formation of an air-buffer layer, textured and inclined sidewalls.
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