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

Gallium oxide (Ga 2 O 3 ) 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-Ga 2 O 3 nanobelts grown by carbothermal reduction without catalyst. The influences of annealing treatment for devices were investigated. The increase of annealing temperature (T a ) improved the SBPD's performance greatly. Ultra-low dark currents of ∼0.89 ​pA and ∼3.58 ​pA at 20 ​V were achieved after T a ​= ​500 ​°C and 550 ​°C annealing process, respectively. Meanwhile, at the optimal T a of 550 ​°C, the device achieves excellent performance: high photo-to-dark current ratio of more than 10 6 , high responsivity (867 A/W), high external quantum efficiency (4.2 ​× ​10 5 %), and high detectivity (1.8 ​× ​10 15 cmHz 1/2 W −1 (Jones)). • High quality single crystal β-Ga 2 O 3 nanobelts are grown by carbonthermic reduction without catalyst. • Metal-semiconductor-metal (MSM) solar-blind photodetectors (SBPD) were fabricated based on these grown nanobelts. • The increase of annealing temperature (T a ) improved the SBPD's performance greatly. • At the optimal T a of 550 ​°C, the device achieves the excellent performance.