Al-doped ZnO thin-film transistor embedded micro-cantilever as a piezoresistive sensor

In this work, an aluminium-doped zinc oxide (AZO) thin film transistor, embedded in a polymer micro-cantilever, is demonstrated for nano-mechanical sensing applications. This device senses the surface stress due to a change in the carrier mobility of the semi-conducting layer. Due to the low Young's modulus and high strain sensitivity of the AZO layer, this micro-cantilever shows a deflection sensitivity of 116 ppm per nanometer of deflection. Also, mechanical characterization of these devices shows that the resonance frequency is in the range of a few tens of kilohertz which is suitable for sensor applications.