Piezotronics and piezo-phototronics - From single nanodevices to array of devices and then to integrated functional system

Due to the polarization of ions in a crystal that has non-central symmetry in piezoelectric-semiconductors such as ZnO, GaN and InN, piezoelectric polarization charges are created at the interface region by applying a strain, which created a potential (piezopotential) in the crystal. Piezotronics is about the devices fabricated using the piezopotential as a gate voltage to tune/control charge carrier transport at a contact or junction. The piezo-phototronic effect is to use the piezopotential to control the carrier generation, transport, separation and/or recombination for improving the performance of optoelectronic devices, such as solar cell and LED. Starting from the fundamental physics principles, this article gives an updated review about the fabrication of array of piezotronic devices so that they can be integrated into a system for achieving specific functions as sensors and MEMS. This first demonstration of fabricating array of piezotronic devices and integrated them into a system is a major milestone in nanotechnology, and it represents one of the promising directions of nanoelectronics. (C) 2013 Elsevier Ltd. All rights reserved.