InGaN/GaN Light-Emitting Diodes with Rapidly Thermal-Annealed Ni/ITO p-Contacts

Ni (5 nm)/Au (5 nm) and Ni (5 nm)/ITO (60 nm) films were deposited onto glass substrates, p-GaN epitaxial layers and nitride-based light-emitting diode (LED) structures. The normalized transmittance of subjected to rapid thermal annealing at 300 C Ni/ITO film (300 C-RTA) could reach 90.1% at 460 nm, which was much larger than that of the Ni/Au film. The specific contact resistances were 5.0 x 10-4, 1.3 x 10-3, and 7.2 x 10-4 OHM cm2 for the Ni/Au, Ni/ITO and 300 C-RTA Ni/ITO contacts on p-GaN, resp. Nitride-based LEDs with these p-contact layers were also fabricated. The LED with the 300 C-RTA Ni/ITO p-contact has a reasonably small operation voltage (i.e., 3.29 V at 20 mA). The 20 mA output intensity of the LED with the 300 C-RTA Ni/ITO p-contact is also 65% larger than that of the LED with the Ni/Au p-contact. 16 refs.