Performance optimization of AlGaN-based LEDs by use of ultraviolet-transparent indium tin oxide: Effect of in situ contact treatment

Ultraviolet (UV)-transparent indium tin oxide (ITO) grown by metal-organic chemical vapor deposition (MOCVD) is used as the current-spreading layer for 368nm AlGaN-based light-emitting diodes (LEDs). By performing in situ contact treatment on the LED/ITO interface, the morphology, resistivity, and contact resistance of electrodes become controllable. Resistivity of 2.64 x 10(-4) Omega cm and transmittance at 368nm of 95.9% are realized for an ITO thin film grown with Sn-purge in situ treatment. Therefore, the high-power operating voltage decreases from 3.94 V (without treatment) to 3.83V (with treatment). The improved performance is attributed to the lowering of the tunneling barrier at the LED/ITO interface. (C) 2018 The Japan Society of Applied Physics