Effect of Asymmetry Mechanical Loads on the Potential Barrier Region of a Piezoelectric pn Junction.

The nonlinear governing equations on the coupling between electromechanical fields and charge carrier in a thermal equilibrium piezoelectric pn junction subjected to asymmetric mechanical loads are established in this article. Effect of mechanical loads on the basic physical parameters of a piezoelectric pn junction, such as potential barrier region width, contact potential difference, electric potential, and carrier concentrations are analyzed numerically. Results show that asymmetry compressive stresses exert more influence on the movement of the potential barrier region's boundary and the migration of carrier compare to asymmetry tensile stresses. It is also found that asymmetry compressive stresses lead to a pn junction with a thin potential barrier region which enhances the chance of carrier's passing through of potential barrier region. The obtained results are useful in reducing the disadvantage of capacitance on rectification characteristic and can be used to tune the I - V characteristic of the pn junction working with bias voltage.