Polymeric Cantilevered Piezotronic Strain Microsensors Processed By Atomic Layer Deposition

We propose an original and reliable method for processing cantilevered piezotronic strain microsensors based on diode junctions made of dominant wurtzite zinc oxide (ZnO) polycrystalline thin film by atomic layer deposition (ALD). These strain sensitive microsensors are integrated into millimetre-sized poly-imide cantilevers by means of maskless laser lithography on the polymer foil, where the zinc oxide thin film is microstructured on top of patterned interdigitated platinum microelectrodes. We show how the structural and transducing properties are strongly influenced by the ALD deposition parameters, leading to the expected Schottky barrier modulation by electromechanical coupling. The linearity, sensitivity, frequency response and noise figure of the created piezotronic strain sensors are reported, leading to measured gauge factors as high as 150. Electrical power consumption inferior to 50 mu W is reported. (C) 2020 The Authors. Published by Elsevier B.V.