Reinforcement of double built-in electric fields in spiro-MeOTAD/Ga2O3/Si p–i–n structure for a high-sensitivity solar-blind UV photovoltaic detector

Abstract

A novel p–i–n self-powered solar-blind UV photodetector based on p-type spiro-MeOTAD (spiro), Ga₂O₃, and n-type Si is fabricated. The p-type spiro film is spin-coated on the surface of the Ga₂O₃ film deposited on a Si wafer via a metal–organic chemical vapor deposition (MOCVD) system. Benefitting from the superior carrier-separation ability of the double built-in electric fields, the effective carrier transport of the novel vertical structure and the high solar-blind UV transmittance of the spiro film, the self-powered responsivity of the p–i–n-type photodetector based on spiro/Ga₂O₃/Si increases to 4.43 mA W⁻¹ under UV light (λ = 254 nm), which is ∼54-fold that of the Ga₂O₃/Si photodetector (0.22 mA W⁻¹). Meanwhile, the response speed (0.03/0.196 s) of the p–i–n device is also dramatically improved by introducing the spiro layer. The reported achievements of our work provide a new way to construct a high-sensitivity self-powered UV photodetector for photovoltaic and optoelectronic applications.