Submitted Abstract
The objectives of this CORE proposal are to rationalize the understanding and the use of piezotronic effect for the next generation of miniaturized strain self-sensors. We will take advantage of the high gauge factor due to the piezotronic effect for the microfabrication of high sensitive self-sensing AFM cantilevers.The piezotronic effect exists in heterojunction systems with one material being a piezoelectric semiconductor and the other being a metal or a semiconductor. When the piezoelectric material is deformed, polarization charges are induced at the Schottky junction between the two materials, which modify the interfacial band structure and thus the carrier transport, trapping, generation, and recombination properties. Hence, piezotronic effect can be summarized as a change of the interfacial carrier dynamics due to the piezoelectric polarization. Because the diffusion current depends exponentially on the Schottky barrier height, the relationship between strain and current flow is also exponential producing very high gauge factor until 4000. That is a breakthrough in sensitivity compared to pure piezoresistive effect or piezoelectric sensing.The project aims at investigating and rationalizing the critical parameters which control the sensitivity, linearity and noise figure of piezotronic strain sensors. As the relevant outputs of this CORE proposal, material processing of zinc oxide for piezotronic sensing, microelectrodes and microstructures realizations, and a demonstrator as an AFM cantilever with a piezotronic strain sensor will be delivered.As expected outcomes, this project will increase necessary scientific and technology knowledge in the field of electromechanical sensors based on the piezotronic effect. The fundamental work is designed to find its applications scope into microsensors for atomic force microscope probes.