Effect of annealing on solar blind photodetector based on β-Ga2O3 nanobelt grown by carbothermal reduction

Abstract

Gallium oxide (Ga2O3) is the promising material for the solar-blind photodetector (SBPD) because of its ultra-wide energy band gap. In this paper, the metal-semiconductor-metal (MSM) SBPDs were fabricated based on the high quality single crystal β-Ga2O3 nanobelts grown by carbothermal reduction without catalyst. The influences of annealing treatment for devices were investigated. The increase of annealing temperature (Ta) improved the SBPD's performance greatly. Ultra-low dark currents of ∼0.89 ​pA and ∼3.58 ​pA at 20 ​V were achieved after Ta ​= ​500 ​°C and 550 ​°C annealing process, respectively. Meanwhile, at the optimal Ta of 550 ​°C, the device achieves excellent performance: high photo-to-dark current ratio of more than 106, high responsivity (867 A/W), high external quantum efficiency (4.2 ​× ​105%), and high detectivity (1.8 ​× ​1015 cmHz1/2W−1 (Jones)).