Piezotransistive GaN Microcantilever Based N02Sensing Using Functionalized Nanoscale Thin Films

In the recent years, microcantilevers with promising deflection sensitivities have been extensively studied in numerous applications including gas sensors. In this study, NO
₂
detection experiment has been demonstrated via piezotransistive GaN microcantilevers utilizing the Kelvin probe measurement technique which is based on the electrostatic force detection between the cantilever tip and In
₂
O
₃
nanoscale thin film. Change in the surface work function of the In
₂
O
₃
thin film due to the exposure to 5 ppm NO
₂
is potentiometrically measured by GaN microcantilevers with an embedded AlGaN/GaN HFET at the base, where the oscillation amplitudes of the microcantilever were directly transduced into electrical signals. Since the GaN microcantilevers does not require any other deflection detection mechanism, it is suitable for practical real time applications.