A new size-dependent nonlinear model for piezoelectric semiconductor nanofibers by considering the effects of strain gradient and flexoelectricity

Flexotronics induced by the strain gradient and flexoelectricity in a semiconductor with symmetric or asymmetric crystal structures have attracted considerable attention as a promising approach for tunable electronic processes. However, the electric nonlinear properties between the carriers and electric field are ignored in most of related studies. In this study, a new size-dependent nonlinear model is developed to investigate the interaction among the size effects (caused by strain gradient and flexoelectricity), piezo-effects and semiconducting properties in a piezoelectric semiconductor (PS) nanofiber with asymmetric crystal structures. In addition, the VonK ' arm ' an's nonlinear strain is also considered to check the effect of geometric nonlinearity. It is found that the piezo-effect can be enhanced (reduced) by the effect of flexoelectricity (strain gradient) due to a new positive (negative) superimposed increment of electric field under a pair of tensile stress. Besides, the size effect will be weakened by the semiconducting property. The studies will provide guidance for theoretical analysis of size effect in nano PSs and design of flexotronic devices.