Emission Intensity Improvement of InGaN Ultraviolet Light-Emitting Diodes Grown on Wet-Etched Sapphire Substrates

Wet-etched pattern sapphire substrates (PSS) with stripes along the <11-20>_sapphire direction are fabricated and investigated. Dislocation reduction and light extraction enhancement are observed for the material grown these substrates. 400 nm UV LEDs with output power enhancement as much as 87% have been demonstrated on the substrate with a 0.9 mum etching depth. The enhancement of output power is thus attributed to the reduction of dislocation density as well as increased light extraction efficiency by the stripe-PSS.