Demonstration of ohmic contact using ${{\rm MoO}_{\rm x}}/{\rm Al}$MoO/Al on p-GaN and the proposal of a reflective electrode for AlGaN-based DUV-LEDs.

The ${{\rm MoO}{\rm x}}/{\rm Al}$MoO/Al electrode was designed and fabricated on p-GaN and sapphire with good ohmic behavior and decent deep ultraviolet (DUV) reflectivity, respectively. The influences of ${{\rm MoO}{\rm x}}$MoO thickness and annealing condition on the electrical and optical behaviors of the ${{\rm MoO}{\rm x}}/{\rm Al}$MoO/Al structure were investigated. Surface morphology of ${{\rm MoO}{\rm x}}$MoO with different thicknesses reveals a 3D growth mode. Partial decomposition of ${{\rm MoO}{\rm x}}$MoO was discovered, which helps in the formation of ohmic contact between ${{\rm MoO}{\rm x}}$MoO and Al. The potential for application in deep ultraviolet light-emitting-diodes (DUV-LEDs) has also been demonstrated.