Beta gallium oxide (β-Ga2O3) nanoelectromechanical transducer for dual-modality solar-blind ultraviolet light detection

Empowered by an ultrawide bandgap (E-g = 4.5-4.9 eV), beta gallium oxide (beta-Ga2O3) crystal is an ideal material for solar-blind ultraviolet (SBUV, lambda < 280 nm) detection. Here, we report on the first demonstration of dual-modality SBUV light sensing integrated in the same device enabled by multi-physics coupling across photo-electrical and photo-thermo-mechanical domains. The specially designed suspended beta-Ga2O3 nanoelectromechanical systems (NEMS) transducer reveals dual-modality responses, with a photocurrent responsivity of 4 mA/W and a frequency shift responsivity of 250 Hz/nW, upon SBUV light exposure. An additional demonstration of a beta-Ga2O3 photo-field-effect transistor exhibits a boosted responsivity of 63 A/W. Analysis on the device suggests that reducing the thickness and length of the transducer could further improve the SBUV light sensing responsivities for both modalities. The demonstration could pave the way for future realization of SBUV detectors with dual modalities for enhanced detection fidelity, or respectively optimized for different sensing scenarios. (C) 2019 Author(s).