InN-based anion selective sensing devices

Ion selective electrodes (ISEs) and ion selective field effect transistors (ISFETs) based on indium nitride (InN) film were used for detecting anions in aqueous solutions. The positively charged surface states on InN surfaces selectively adsorbed anions, building Helmholtz voltages near the InN/solution interface was confirmed using open-circuit potentiometric and I-V measurements. The InN-based ISE obeyed the Nernst equation with the sensitivity of 45 and 49 mV/decade for chloride and hydroxyl ions, showing remarkable selectivity, response time, stability and repeatability. Ultrathin (~10 nm) InN ISFETs demonstrated ion sensing with a sensitivity of 5 ¿A per decade and a response time less than 10s. Molecular-beam epitaxy (MBE) system was used to conduct the epitaxial growth of InN film on Si (111) substrate, enabling the InN based chemical sensors to integrate with the wireless sensors on the same chip to transmit real-time sensing data.