Effect of flexoelectricity on piezotronic responses of a piezoelectric semiconductor bilayer

Abstract

Based on three-dimensional equations of piezoelectric semiconductors, we take flexoelectricity into consideration to develop a deformation-polarization-carrier coupling analysis model for the bending of a piezoelectric semiconductor (PS) composite bilayer, which is composed of a piezoelectric semiconductor layer and an elastic layer. Using the derived equations, we investigate the macroscopic responses, such as the distribution of electromechanical field and carrier concentration, of the PS composite bilayer with bending deformation. The induced polarization in the PS composite bilayer exhibits an apparent size-dependent property due to the flexoelectric coupling effect, and thus has a remarkable influence on the piezotronic effect in the PS composite bilayer with nano-thickness. The obtained results are useful for designing novel piezoelectric semiconductor devices.