Beta Gallium Oxide ($\beta$-Ga2O3) Vibrating Channel Transistor

We report on the first demonstration of an ultra-wide bandgap (UWBG), single-crystal $\beta$-Ga2O3 vibrating channel transistor (VCT), with all-electrical actuation and detection enabled by efficient vibration-induced channel conductance modulation. Given the challenges in making functional transistors in nanometer-thick $\beta$-Ga2O3 with appreciable on-state current and gating effect, directly coupling motion into transistors of this UWBG crystal has been elusive and not been explored yet. Here, we engineer the thickness of suspended $\beta$-Ga2O3 channel to attain a favorable threshold voltage ($\vert V_{\mathrm{th}}\vert < 35\mathrm{V}$), and operate the device in the subthreshold regime for optimal electromechanical coupling. A lithographically defined local gate device structure on insulating substrate and frequency modulation (FM) mixing techniques are employed for the VCT to suppress parasitic background, leading to enhanced transduction of the first $\beta$-Ga2O3 VCT resonance at ∼26MHz. The realization of all-electrical readout of $\beta$-Ga2O3 VCT resonators with local gates paves a way for integrating $\beta$-Ga2O3 nanoelectromechanical resonators with individual device addressability into the rapidly developing $\beta$-Ga2O3 electronics for on-chip sensing, communication, and computing functionalities.