Analysis Of Multi-field Coupling Mechanical Behavior Of Laminated Piezoelectric Semiconductor Structures

Piezoelectric semiconductors(PSs),which exhibit piezoelectricity and semiconductor properties,are the promising building blocks of novel functional and smart devices.They have a huge potential application in the fields of information,energy,biology,medicine,aerospace and so on.Laminated piezoelectric semiconductors are common-used device structures.Theoretical analysis of multi-field coupling mechanical behaviors of piezoelectric semiconductors plays a crucial role in the development and design of semiconductor devices.Following the structural theory systemized by R.D.Mindlin,the thesis establishes a system of two dimensional(2D)equations for N-layered piezoelectric semiconductor plates on the basis of the continuum mechanics theory and fundamentals of semiconductor physics.The nonlinear equations for drift currents of electrons and holes are linearized for a small carrier concentration perturbation,the displacement,potential and the incremental concentration of electrons and holes are expanded in the power series of the plate thickness.For a thin-film cantilever PS plate composed of Ag/n-type ZnO/Al/PET substrate,the analytical expressions of the electromechanical fields and distribution of electrons in the PS plate subjected to static and dynamic cylindrical bending are presented,respectively.The numerical results show that the electromechanical behaviors can be effectively controlled by the external applied force,driving frequency and initial concentration of carriers.The results demonstrated in this thesis,meaningful for engineering application,provide important theoretical guidance in the analysis of PS devices.