Generalized Rayleigh Wave In Piezoelectric Semiconductor Layered Structure Considering Rotation Effect

The gyro effect caused by the rotation of the structure will cause the wave propagation characteristics to change.Piezoelectric semiconductor materials are gradually used for manufacturing SAW devices because they have both electromechanical coupling characteristics and semiconductor characteristics.This paper studies the effect of rotation on the propagation characteristics of generalized Rayleigh waves in different piezoelectric semiconductor structures.The main contents include three parts:First,the generalized Rayleigh wave in a rotation piezoelectric semiconductor half space is studied.A piezoelectric semiconductor half space model is established and the structure is rotated around a fixed axis.Based on the theory of elastic dynamics and piezoelectric semiconductor,the field control equations represented by displacement function,potential function,and disturbed carrier concentration function are derived.The dispersion equation is obtained by combining trial solutions and boundary conditions and the minimum modulus approximation method is used for numerical solution.The research results show that the phase velocity and attenuation of the generalized Rayleigh wave are approximately linear with the angular velocity.Rotation under different electrical boundaries changes the attenuation of the wave,and the biased electric field give rise to a small change of the effect of rotation on phase velocity and attenuation.Second,a layered structure model that is closer to practical application structure is established.Piezoelectric semiconductor materials and elastic materials are selected as the cover layer and the substrate,and the elastic substrate is regarded as a half space.Considering the rotation of the structure,the corresponding field governing equations are established and solved.The numerical results show that the phase velocity and attenuation of the generalized Rayleigh wave are approximately linear with the angular velocity in the calculation range,and both of them change with the thickness of the piezoelectric semiconductor layer at the same angular velocity.The biased electric field causes the generalized Rayleigh wave to gain,and it angular velocity.The biased electric field causes the generalized Rayleigh wave to gain,and it can change the degree of the influence of rotation on phase velocity and attenuation.Final,based on the model of the rotating piezoelectric semiconductor layered structure,considering the initial stress in the cover layer without a bias electric field and the initial stress and initial electrical displacement caused by the applied bias electric field,the effect of initial stress and initial electrical displacement on the propagation characteristics of generalized Rayleigh wave are investigated.It is assumed that the initial stress in the piezoelectric semiconductor layer is constant,and the relationship between the bias electric field and initial stress and the initial electrical displacement are derived.The field governing equations under different conditions are established and solved respectively.The numerical results show that the initial stress in the piezoelectric semiconductor layer will change the phase velocity of the generalized Rayleigh wave and weaken the attenuation of the wave amplitude.Within a certain range of wave number,the wave gain can be obtained by applying an appropriate bias electric field.Through the above research,it is found that the rotation has effects on the generalized Rayleigh wave propagation characteristics in different piezoelectric semiconductor structures,and these effects can be adjusted by applying a bias electric field.