Non-homogeneous cross section variation enhanced flexoelectric coupling in semiconductor beams and its application in charge carrier redistribution.

A pure bending semiconductor beam that exhibits a non-homogeneous cross section variation enhanced flexoelectric coupling effect is investigated in this paper from the point of view of theoretical analysis and numerical calculations. According to the macroscopic theory of flexoelectric semiconductors, a one-dimensional bending model for a simple-supported beam with variable cross section is developed. The semi-analytical method, which is composed of cosine series and supplementary functions, is introduced to solve the partial differential equations with variable coefficients. Before the analysis, the convergence and correctness of the semi-analytical method are demonstrated systematically. The calculated results show that both the electric potential and the charge carrier distribute non-homogeneously in the entire beam under a pair of symmetric bending moments. It is revealed that more carriers, a larger electric potential, and more charges tend to concentrate in the zone near the ends. After introducing a dimensionless carrier density, this paper systematically investigates the non-homogeneous cross section variation effect on the flexoelectric coupling for charge carrier redistribution. It is indicated that more perturbation carriers in a non-uniform beam are produced by the enhanced flexoelectric coupling. The demonstration of this concept could be potential guidance for designing new semiconductor devices. [ABSTRACT FROM AUTHOR]