Improvement of the reverse leakage behavior of Ag-based ohmic contacts for GaN-based light-emitting diodes using MgZnO interlayer

MgZnO(MZO) interlayers are introduced to form high-quality Ag-based ohmic contacts to p-type GaN (N_a = 4 × 10¹⁷ cm^-3) for GaN-based flip-chip light-emitting diodes (LEDs). The MZO (2.5 nm)/Ag (250 nm) contacts become ohmic with specific contact resistance of 3.83 × 10^-4 Ω cm² and reflectance of ∼83% at a wavelength of 405 nm when annealed at 530 °C for 1 min in air. It is shown that LEDs made with the MZO interlayers yield reverse leakage currents three orders of magnitude lower than that of LEDs without the interlayers. In addition, the LEDs fabricated with the MZO interlayers show higher output power as compared with the LEDs without the interlayers.