Enhanced detectivity self-powered (photovoltaic) solar-blind UV-C Sn-doped β-Ga2O3-based photodetectors via Sn+-implantation with outstanding dark current suppression

Self-powered solar-blind Ga ₂ O ₃ -based photodetectors (PDs) encounter several challenges, including demanding and complex fabrication processes that substantially increase production costs. However, cost-effective simple device structures based on a single Ga ₂ O ₃ layer do not exhibit adequate performance due to high dark current. In this report, these challenges are addressed by employing Sn ⁺ implantation and post-implantation annealing of β-Ga ₂ O ₃ epilayers grown by pulsed laser deposition (PLD), enhancing the performance of the resulting metal − semiconductor − metal (MSM) PDs. As-grown β-Ga ₂ O ₃ film-based PDs are characterized by high dark current, a slow photoresponse (several seconds), and a weak on/off ratio (~ 10). We show that Sn ⁺ implantation and post-implantation annealing suppresses the dark current completely as bias increases, yielding an exceptionally superior photocurrent-to-dark current ratio (~ 10 ⁹ ) and faster photoresponse (< 40 ms). We also demonstrate significant detectivity enhancement by a factor of 10 ⁵ , along with a significant solar-blind rejection ratio (~ 10 ⁴ ), a sharp cut-off at 265 nm (UV-C region), as well as excellent self-powered characteristics of implantation-based devices. X-ray photoelectron spectroscopy and density functional theory reveal the possible causes of such improvements. This is the first investigation of self-powered solar-blind DUV PDs based solely on a single Sn ⁺ -implanted β-Ga ₂ O ₃ layer.