Influence Of Flexoelectricity And Strain Gradient Effect On The Bending Vibration Characteristics Of Piezoelectric Semiconductor Nanowires

Piezoelectric semiconductor materials have dual physical properties of piezoelectricity and semiconductor at the same time,and have received more and more attention in the research and application of smart devices and structures.Nowadays,piezoelectric semiconductor materials at the micro-nano scale are the main research direction,but with the shrinking of the research size,the scale effect is gradually not negligible,and the strain gradient effect and the flexoelectricity effect will affect the electromechanical behavior of the structure.This article first establishes a piezoelectric semiconductor nanowire cantilever beam structure model,in which the end of the cantilever is subjected to harmonic shear forces.Based on that,this article has done the following research:(1)Considering the static flexoelectricity effect and the strain gradient effect,the basic equations are established and theoretically deduced according to the Hamilton principle,and the analytical expressions of deflection,rotation angle,electric potential and carrier concentration are obtained.By changing the values of static flexoelectricity coefficient and intrinsic scale coefficient,we can explore their influence on the physical field and structure of nanowires.The research results show that the static flexoelectricity effect and the strain gradient effect will affect the vibration frequency and physical field distribution of the structure at the micro-nano scale.The larger the two effect coefficients,the more obvious the effect.(2)On the basis of considering static flexoelectricity effects and strain gradient effects,the dynamic flexoelectricity effects are also considered,the basic equations are established and theoretically deduced,and the analytical expressions of deflection,rotation angle,electric potential and carrier concentration are obtained.Changing the dynamic flexoelectricity coefficient,the four physical fields of deflection,rotation angle,electric potential and carrier concentration have different degrees of change.The research results show that the increase of the dynamic flexoelectricity coefficient will reduce the natural frequency,reduce the stiffness of the nanowire,and affect the distribution of the force and electric field.The research results in this paper show that when static flexoelectricity,dynamic flexoelectricity and strain gradient effects increase,their influence on the electromechanical coupling performance of piezoelectric semiconductor nanowires has a tendency to increase.It provides a positive guiding role for the research and development of new smart materials at the micro-nano scale.