Wireless UV sensor based on photocapacitive effect in GaN

The LC oscillator with the interdigitated aluminium-on-GaN/sapphire photocapacitor has been demonstrated. Upon illumination with a 375 nm UV LED, an oscillator frequency downshift owing to the photocapacitive effect attains 5.2 MHz (3.5 % of the dark frequency value 149 MHz) with sensitivity up to 170 kHz/(µW/cm2). The oscillator can be employed as a visible-blind UV sensor with a remote wireless pickup of the RF output signal.