High responsivity in molecular beam epitaxy grown β-Ga2O3 metal semiconductor metal solar blind deep-UV photodetector

Abstract

In this report, we demonstrate high spectral responsivity (SR) in MBE grown epitaxial β-Ga2O3-based solar blind metal-semiconductor-metal (MSM) photodetectors (PD). The (-201)-oriented β-Ga2O3 thin film was grown using plasma-assisted MBE on c-plane sapphire substrates. MSM devices fabricated with Ni/Au contacts in an interdigitated geometry were found to exhibit peak SR > 1.5 A/W at 236–240 nm at a bias of 4 V with a UV to visible rejection ratio > 105. The devices exhibited very low dark current < 10 nA at 20 V and showed no persistent photoconductivity (PPC) as evident from the sharp transients with a photo-to-dark current ratio > 103. These results represent the state-of-art performance for the MBE-grown β-Ga2O3 MSM solar blind detector.