Analysis of static extension of piezoelectric semiconductor nanowires considering non-uniform strain and flexoelectric effects

Piezoelectric semiconductor (PSC) nanowires have a great potential to be the basic element of the next generation of micro and nano electro-mechanical systems. A lack of understanding of their electromechanical coupling behaviors can be a major obstacle to using PSC nanowires. In this paper, a one-dimensional model is proposed to investigate the electromechanical coupling behavior of PSC nanowires under static extension. In the present model, effects of piezoelectricity and flexoelectricity are considered simultaneously. Closed-form expressions for the distributions of electron concentrations and electromechanical fields are obtained. The effects of applied distributed traction force, flexoelectric effect and initial carrier concentration have been discussed. Results show that the distributions of electromechanical fields predicted by the present model are different from those of the classical model (which only considers piezoelectric effect). For example, the applied uniform distributed traction force breaks the symmetrical distributions of electromechanical fields, resulting in the redistribution of electron concentrations. However, flexoelectricity shows a significant weakening effect on the values of relevant electromechanical fields. This research offers a new method to tune the electromechanical coupling characteristics of piezoelectric semiconductor materials.