Monolithic integration of nitride-based transistor with Light Emitting Diode for sensing applications

A novel monolithically-integrated LED and HEMT sensor, based on III-nitrides, is designed and realized. The main aspects of the design and processing issues of such a device are presented and discussed. Satisfactory operation of both LED and HEMT parts of the device was ascertained by means of electrical characterization. The best obtained turn-on voltage for the LED part of the device was as low as ∼4.5 V, which is quite acceptable for nitrides, while the IDSsat value of ∼26 mA/mm for the HEMT part, is rather low as compared to typical AlGaN/GaN HEMTs. Moreover, intense light emission was readily obtained from the LED, with a large portion of light illuminating the sensor active area. The overall satisfying performance of the integrated device opens the way for actual sensing experiments to be performed.