Torque-tuned I-V characteristics in a piezoelectric semiconductor composite fiber

This paper studies the multi-physical fields in a torsional composite fiber composed of a non-piezoelectric semiconductor (PS) core coated with a piezoelectric dielectric shell. Based on the three-dimensional framework of piezoelectricity and drift-diffusion theory, we develop a nonlinear one-dimensional model that incorporates the warping deformation, shear deformation, and axial variations of the electric field and charge transportations. A One-dimensional model is linearized for small perturbations of charges, and we obtain the analytical solutions for single rods or PN junctions when torques are applied, which explicitly illustrates the electromechanical fields and redistribution of mobile charges. We also examine how the thickness of the composite rods affects the interaction between the piezoelectric and semiconductor components in the model. The optimal thickness ratio for maximizing the overall mobility of carriers has been discovered. This enables us to modify the thickness ratio to achieve the greatest PS interaction performance. Based on the nonlinear equations, we analyze the relationships between electric currents and applied voltages on the end of rods. Finally, we examine how twisting moments influence the characteristics of this I-V relationship. The presented study provides a potential application for mechanical switches or sensors for PSs.