Research On Mechanical Behaviors Of One-Dimensional Piezoelectric Semiconductor Rods

Piezoelectric semiconductors(PS)simultaneously possess piezoelectricity and semiconductor properties.The piezoelectric potential will be produced in piezoelectric semiconductors under an external force,which can be used to control semiconductor properties in piezoelectric semiconductors.It makes piezoelectric semiconductors have huge potential applications in future novel multi-functional devices.Theoretical researches on mechanical behaviors of piezoelectric semiconductors will provide a helpful theoretical guide for innovative development and design of PS devices.Hence,this master's thesis investigates the mechanical behaviors of one-dimensional PS rods,and the following three parts of research work are conducted.Firstly,a piezoelectric semiconductor rod which is free from external forces and electric fields is analyzed by taking the nonlinear coupling term into account,and analytical solutions are obtained.Numerical results show that the PS rod is under axial extension in one side and under axial contraction in the other side,the electromechanical fields and carrier distribution in the PS rod vary more rapidly near the ends of the fiber than in the central part.Secondly,a piezoelectric semiconductor rod which is under the action of a pair of equal and opposite axial force is investigated,analytical solutions are obtained with the linearization method.Numerical results show that the electromechanical fields and carrier distribution near two ends of the rod are stronger than those in the central part of the rod.Besides,the electric field,electric displacement,strain and displacement in the rod displace a symmetrical distribution along the middle point of the rod.Finally,a cantilever piezoelectric semiconductor rod,which is under a transverse end force,is studied.Similarly,using the linearization method,we obtain analytical solutions for the bending and shear of the cantilever PS rod.Numerical results show that the electric potential and carrier distributions are nearly a constant for the most part along the fiber except near its fixed end.