A general strategy for enhancing the performance of Ga₂O₃-based self-powered solar-blind photodetectors through band structure engineering

Abstract The spectral response of Ga 2 O 3 almost perfectly covers the 200–280 nm solar-blind ultraviolet wavelength range, making it an ideal semiconductor material for fabricating solar-blind ultraviolet photodetectors. However, due to the considerably deep valence band energy of Ga 2 O 3 the construction of heterojunctions typically induces a significant valence band offset (Δ Ev ). Herein, we present a band engineering approach to improve the performance of Ga 2 O 3 bases photodetectors. This pronounced valence band barrier can strongly influence the transport of photo-generated charge carriers, especially the extraction of holes in the depletion region. By introducing nitrogen (N) during the growth process, we elevated the valence band of Ga 2 O 3 by 0.43 eV. The organic high-molecular-weight material of PEDOT:PSS has been utilized in conjunction with Ga 2 O 3 to construct heterojunction photodetectors. The photodetectors exhibit excellent self-powered characteristics, with responsivity, detectivity, and response time being nearly ten times higher than those of Ga 2 O 3 photodetectors before band structure modulation. The investigation into modulating the band structure of Ga 2 O 3 carried out in this study will lay the theoretical foundation and provide technical solutions for developing satisfactory self-powered photodetectors.