Highly transparent and low-resistant ZnNi/indium tin oxide Ohmic contact on p-type GaN

Abstract

The authors report the improvement of GaN light-emitting diodes (LEDs) by applying a ZnNi/indium tin oxide (ITO) (5nm∕380nm) electrode with high transparency and low resistance to p-GaN. The Pt/ITO (5nm∕380nm), Ni∕Au∕ITO (2.5nm∕5nm∕380nm), and Ni∕Au (2.5nm∕5nm) electrodes were prepared and annealed at 400, 500, and 600°C for 1min in air. The ZnNi/ITO contacts showed the lowest specific contact resistance of ∼1.27×10−4Ωcm2 and the highest transmittance of ∼90% at 460nm. LEDs fabricated with ZnNi/ITO p electrodes showed the best performance with a forward voltage of 3.28V and a typical brightness of 11. 7mcd at 20mA.