Gallium Nitride-Based Chemical Sensors

The rapid progress in semiconductor materials and devices has promoted the development of the sensors industry. Large band gap semiconductors are ideal candidates for a variety of sensor applications. In particular, gallium nitride (GaN) is used as the sensing element for the development of chemical sensors. The recognition mechanism is based on the selective interaction of anions in solution with the epitaxial Ga-face polarity GaN wurtzite crystal film, grown on sapphire. The native GaN crystal is used for the development of ion sensors. Also AlGaN/GaN high electron mobility transistors can be used as sensing elements by monitoring the drain source current. The chemical resistivity of the GaN crystal favours sensors with excellent lifetime, signal stability, and reproducibility.