Fast Response (7.6s) Acetone Sensing by InGaN/GaN on Si (111) at 373 K

A new and exciting resistive gas sensor based on Ni/InGaN/GaN heterostructure, grown by plasma-assisted molecular beam epitaxy, has been developed to efficiently detect acetone very rapidly at low temperature. Non-rectifying I-V characteristics of epitaxially relaxed InGaN with Ni contact have been revealed at 373 K. An incremental current of 11.74 μA has been found at 373 K with the exposure of 100 ppm of acetone vapor at an operating bias of 0.4 V. Sensitivity has been obtained from transient response curves. Most importantly, very fast response/recovery characteristics with good baseline recovery have been witnessed. The response time and recovery time have been found to be ~7.6-8.4 s and ~4.5-19.1 s. A possible explanation, including Langmuir adsorption-desorption isotherm, has also been discussed.