Enhancing Performance of Ultraviolet C Photodetectors Through Single-Domain Epitaxy of Monoclinic β-Ga2O3 Films and Tailored Anti-Reflection Coating

Implementing high-performance ultraviolet C photodetectors (UVC PDs) based on beta-Ga2O3 films is challenging owing to the anisotropic crystal symmetry between the epitaxial films and substrates. In this study, highly enhanced state-of-the-art photoelectrical performance is achieved using single-domain epitaxy of monoclinic beta-Ga2O3 films on a hexagonal sapphire substrate. Unlike 3D beta-Ga2O3 films with twin domains, 2D beta-Ga2O3 films exhibit a single domain with a smooth surface and low concentration of point defects, which enable efficient charge separation by suppressing boundary-induced recombination. Furthermore, a tailored anti-reflection coating (ARC) is adopted as a light-absorbing medium to improve charge generation. The tailored nanostructure, which features a gradient refractive index, not only substantially reduces the reflection, but also suppresses the surface leakage current as a passivation layer. This study provides fundamental insights into the single-domain epitaxy of beta-Ga2O3 films and the application of ARC for the development of high-performance UVC PDs.

Automated summary

This study achieved highly enhanced photoelectrical performance of UVC PDs by implementing single-domain epitaxy on a hexagonal sapphire substrate. The 2D beta-Ga2O3 films exhibited a smooth surface and low concentration of point defects, enabling efficient charge separation. Additionally, a tailored anti-reflection coating was adopted to improve charge generation.