Wireless UV sensor based on photocapacitive effect in GaN

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