AlGaN-Based Deep Ultraviolet Light-Emitting Diodes Fabricated on Patterned Sapphire Substrates

Abstract

Deep ultraviolet (DUV) light-emitting diodes (LEDs) on patterned sapphire substrates (PSSs) have been clearly demonstrated. AlN templates grown on PSSs had average threading dislocation densities (TDDs) of as low as 5×107 cm-2. Flip-chip DUV LEDs fabricated on PSSs demonstrated a significantly high performance. The 266 nm LED exhibited an output power of 5.3 mW and an external quantum efficiency (EQE) of 1.9% at 60 mA DC, and the 278 nm LED had 8.4 mW output and an EQE of 3.4%. Moreover, the 70% lifetime was more than 700 h at 20 mA.