Adjusting the electromechanical coupling behaviors of piezoelectric semiconductor nanowires via strain gradient and flexoelectric effects

Abstract

In this paper, the strain gradient is introduced to tune the semiconducting performance of piezoelectric semiconductor (PSC) nanowires by changing their cross sections. A one-dimensional model of the PSC nanowire with a non-homogeneous cross section under axial extension is established. The combined influences of piezoelectricity and flexoelectricity resulting from the strain gradient are taken into account. Approximate closed-form solutions for the distribution of carriers and electromechanical fields of the PSC nanowire are given. The effects of strain gradient, flexoelectricity, and initial carrier concentration on the distribution of carriers, electric field, electric potential, and displacement are discussed. It is observed that non-homogeneous PSC nanowires show strong size-dependent behaviors in connection with their cross-sectional diameters. The strain gradient and flexoelectric effect enhance the electromechanical coupling effect. This research provides a new way to tune inner carrier distributions and electromechanical characteristics for piezoelectric semiconductor devices.

Model and performance analysis of non-uniform piezoelectric semiconductor nanofibers

“…The variable cross-sectional area is represented by a random function A(x 3 ) and a pair of extensional forces F are applied at the two ends. For the equilibrium and the steady states considered, the governing equations become [20]:…”

“…Especially, with the development of modern micromachining, e.g., 3D printing technology, fabricating a non-uniform PS fiber at will is anticipated to achieve sooner and later. However, finding an theoretical solution beyond of FEM [20] to depict the electromechanical fields in a non-uniform PS fiber with random cross sections is still rare, which can't meet the design needs of engineers and scientists. In order to seek a general solution that is suitable for any non-uniform PS fibers with a random cross section, this paper presents a simple approach, i.e., the power series expansion method, to model and analyze the piezotronic performance of PS nanofibers, which is also the highlight of this contribution.…”

Piezoelectric Materials based Phototronics

“…The induced piezoelectric polarisation charges successfully separated the photogenerated MO charge carriers at the heterojunction interface between ZnO and TiO2. The piezo-phototronic phenomenon has also been employed in information storage and calculations involving mechanical-electro-optical logic [90][91][92]. Polarization charges induced by strain at the electrode/CdS interface can control charge carrier optoelectronic processes and electrical transport, allowing opticalmechanical stimuli to be transformed into electronic signals via the piezo-phototronic effect.…”

Impact of PN junction inhomogeneity on the piezoelectric fields of acoustic waves in piezo-semiconductive fibers

“…F is applied at the two ends. For the equilibrium and the steady states considered, the governing equations become [34]:…”