初应力下压电半导体板中SH波的传播特性

针对无限大n-型压电半导体板，论文理论研究了其在初应力作用下水平剪切波的传播特性。基于压电半导体三维宏观理论和边界条件得到色散关系，结合数值算例，系统分析了边界条件、初始载流子浓度、板的厚度和初应力大小对SH波传播特性的影响。此外，讨论了初应力下两种不同材料中的SH波传播。研究显示：较小的初应力对相速度影响很小可忽略，当初应力达到一定值时波速急剧下降；类似地，初应力足够大时衰减才会逐渐加强。计算结果对压电半导体器件设计具有一定的理论指导意义。

SH Wave Propagation in Piezoelectric Semiconductor Plate with Initial Stress

Piezoelectric semiconductors (PSs) have the physical properties of both piezoelectric and semiconductor materials. Devices and structures based on PSs have recently drawn particular attention due to their potential applications in multi-functional electronic devices. The core property of PSs is the interaction between the internal electric field and the charge carrier when under a mechanical force or a bias voltage. In the processing and application of PSs, the existence of initial stress is inevitable. At the same time, the initial stress is usually applied in the manufacturing process in order to prevent brittle fracture of materials. In this paper, the propagation behavior of shear-horizontal (SH) waves in an infinite n-type PS plate with initial stress is studied. The linear macroscopic theory of PSs is used. Based on the three-dimensional equations, the elastic surface wave problem is converted into a homogeneous linear eigenvalue system. Finally, making use of the boundary conditions on the top and bottom surfaces of the PS plate, a transcendental equation that determines the dispersion relation is obtained analytically. Numerical examples are presented to systematically study the effect of boundary condition, steady-state carrier density, plate thickness, and initial stress on the wave speed and attenuation of SH wave. In addition, SH wave propagation in two different PS materials under initial stress is discussed. It is found that the real and imaginary parts of wave velocity under short-circuit are correspondingly smaller than open-circuit boundary. The SH wave characteristics in the PS plate are the same as that in the corresponding piezoelectric plate when the steady-state carrier density is small (the semiconductor properties can be ignored). The results also show that the effect of small initial stress on phase velocity is negligible, and the wave speed decreases sharply when the initial stress reaches a certain value. Similarly, attenuation increases gradually as the initial stress becomes large enough. The calculation results in this paper could be helpful as theoretical guidance when designing PS surface acoustic wave devices.