β-Ga2O3 Schottky diodes based strain gauges with high resistance, large gauge factor, and high operating temperature

Abstract

We report observation of the piezoresistive effect of β-Ga2O3 Schottky diodes and investigate its application for strain gauge sensors. The Schottky diode-based strain gauge exhibits resistance on the order of 107 Ω, which allows low power applications. A large gauge factor of −201 ± 43 is measured from a Pt/(2¯01) β-Ga2O3 Schottky diode at room temperature, enabling the strain-induced resistance change to be measurable without a Wheatstone bridge. Mechanical exfoliation in the (100) surface produces β-Ga2O3 single crystal thin films, which are more suitable for strain gauge applications than bulk substrates. Owing to the wide bandgap nature, we demonstrate high-temperature operation of strain sensing based on β-Ga2O3 Schottky diodes up to 800 K. The β-Ga2O3 Schottky diodes simultaneously function as temperature sensors, which may enable temperature compensation of strain gauge output.