A high-performance solar blind photodetector based on spinel gallium oxide thin film supported by aluminum doping

Abstract

Metastable γ-phase gallium oxide (Ga₂O₃)-based semiconductor materials have recently garnered much attention for developing high-performance wide-band-gap optoelectronic devices. However, the difficulty in the synthesis of single-phase crystals and the poor thermal stability of metastable γ-Ga₂O₃ pose great obstacles for its potential applications. In this work, we experimentally demonstrate the epitaxial growth of γ-Ga₂O₃ thin films at 750 °C on α-Al₂O₃ (0001) substrates upon aluminum (Al) doping. A solar blind photodetector based on an Al-doped γ-Ga₂O₃ thin film was successfully fabricated, and its properties were investigated in detail. Benefiting from its high crystal quality and absence of oxygen vacancies in Al-doped γ-Ga₂O₃, the solar blind photodetector exhibited a very low dark current, fast decay time, high detectivity, and excellent wavelength selectivity, along with high stability and reproducibility. Notably, the present device exhibited no obvious performance degradation when the light intensity and bias voltage were increased, indicating good self-heating dissipation, which is beneficial for future practical applications. The γ-Ga₂O₃ thin film-based photodetector might open up new possibilities to obtain high-performance thin film-based solar blind ultraviolet optoelectronic devices.