We report on a high-transparency low-resistance composite contact structure on p-GaN for light-emitting diode applications. The structure consists of a thin Ni ͑5 nm͒ /Au ͑5 nm͒ layer overcoated with a sputtered Al-doped ZnO ͑170 nm͒ layer. Enhancement in light emission intensity as high as 74% at 40 mA and forward operating voltages in the range of 3.36-3.48 V at 20 mA are obtained for these devices using a two-step thermal annealing process.

This paper presents high-transparency low-resistance contact on p-GaN using oxidized Ni/AuZnO : Al 2 O 3 (2 wt%) for high-performance GaN-based light-emitting diodes (LEDs) applications. It is shown that oxidized Ni/Au -ZnO contact to p-GaN yields an operating voltage of around 4.7 V at 20 mA compared to 4.1 V of a reference oxidized Ni/Au(5 nm/5 nm) -Ni/Au(20 nm/120 nm) sample without the ZnO : Al 2 O 3 (2 wt%) layer. Enhancement of transmittance of about 60% at the wavelength of 450 nm over a conventional N 2 -annealed semi-transparent Ni/Au(5 nm/5 nm) contact is measured on glass substrates.