Photonics Research, 2020, 8 (8): 08001381, Published Online: Jul. 31, 2020
Electrical properties and microstructure formation of V/Al-based n-contacts on high Al mole fraction n-AlGaN layers Download: 875次
Abstract
The electrical and structural properties of V/Al-based n-contacts on with an Al mole fraction ranging from to are investigated. Ohmic n-contacts are obtained up to with a contact resistivity of whereas for higher Al mole fraction the IV characteristics are rectifying. Transmission electron microscopy reveals a thin crystalline AlN layer formed at the metal/semiconductor interface upon thermal annealing. Compositional analysis confirmed an Al enrichment at the interface. The interfacial nitride-based layer in n-contacts on is partly amorphous and heavily contaminated by oxygen. The role and resulting limitations of Al in the metal stack for n-contacts on n-AlGaN with very high Al mole fraction are discussed. Finally, ultraviolet C (UVC) LEDs grown on and emitting at 232 nm are fabricated with an operating voltage of 7.3 V and an emission power of 120 μW at 20 mA in cw operation.
Luca Sulmoni, Frank Mehnke, Anna Mogilatenko, Martin Guttmann, Tim Wernicke, Michael Kneissl. Electrical properties and microstructure formation of V/Al-based n-contacts on high Al mole fraction n-AlGaN layers[J]. Photonics Research, 2020, 8(8): 08001381.