In/ITO p-Type Electrode for High-Brightness GaN-Based Light Emitting Diodes

Indium interlayers (10 nm thick) were used to form highly transparent and low-resistance indium-tin oxide (ITO) (200 nm) ohmic contacts to p-GaN for high-brightness light emitting diodes (LEDs). The In/ITO contacts became ohmic with a specific contact resistance of 1.46× 10-3 cm2 and produced transmittance of 95.8% at wavelength of 460 nm when annealed at 530°C. Blue LEDs fabricated with the annealed In/ITO p-type contact layers exhibited a forward-bias voltage of 3.42 V at an injection current of 20 mA. The light output power of LEDs with the In/ITO contacts was enhanced 91% at 20 mA compared to LEDs with the oxidized NiAu contacts.