III-Nitride Microchips for Sugar Concentration Detection

In this work, a novel GaN-based microchip for sugar concentration detection is reported. Adopting the monolithic integration approach, the emitter and detector are fabricated on a GaN-on-sapphire chip and the transparent sapphire substrate enables optical coupling without external optics. The exposed sapphire boundary provides a reflectance response according to the concentrations of glucose and fructose solutions. The measured photocurrent signals can quantitatively indicate the solution concentration in the range of 5–50 % and a fast response time of 0.24 s is obtained. Through a series of experimental measurements, the microchip exhibits the abilities of real-time monitoring and detection of honey adulteration. The developed microchip provides the notable features of small footprint, high compactness, low cost, ease of operation, making it suitable for practical applications.