Study of nanoscale three dimensional Au/GaN Schottky junctions: Fabrication, morphology and optoelectronic properties

Owing to the effective carrier transfer at interface, the utilization of three-dimensional (3D) Schottky junctions transcends the limitations imposed by planar junctions, exhibiting significant potentials in optoelectronics of plasmon-semiconductor system. However, in nanoscale, widespread adoption of 3D Schottky junctions are significantly hindered by complexities of nanoscale photolithography processes. In this work, the Au/GaN 3D Schottky junctions are fabricated via thermal induced etching process. The etching behavior is investigated in terms of morphology and optical properties. Based 3D Schottky junctions, GaN metal–semiconductor-metal photodetectors are fabricated and the optoelectronic properties of Au/GaN 3D Schottky barriers are investigated. With 3D Schottky junctions, the sensitivity and detectivity have been improved by 20.7 and 3.6 times in comparison with the planar Au/GaN junctions. Meanwhile, the noise equivalent power has been reduced of 76.3%, showing a large improvement in response of small signals.