GaN Schottky diodes for piezoelectric strain sensing

We report on the electromechanical response of Schottky diodes on n-GaN as a function of the strain frequency and the applied dc bias. These measurements reveal excellent strain detection sensitivity for frequencies above ∼10 Hz. The observed amplitude and phase of the electromechanical output can be largely explained using a simple model of piezoelectric charge generation on either side of the depletion layer. In addition, we report on the noise spectral density from these diodes under the same conditions and infer a signal to noise ratio for strain detection.