A mechanically induced artificial potential barrier and its tuning mechanism on performance of piezoelectric PN junctions

A mechanically induced artificial potential barrier (MIAPB) is set up in the paper by a pair of tensile/compressive stresses acted on a piezoelectric PN junction. The action mechanism of MIAPB on the electric characteristics is investigated via a full-coupled model between multi-physical fields and charge carriers. A MIAPB tuning methodology is put forward and the interaction between MIAPB and the interface potential barrier is analyzed in depth. Influences of loading locations of MIAPB on barrier configuration, carrier concentrations and recombination rate are carefully illustrated and the improved I-V characteristics of a ZnO PN junction subjected to MIAPB are obtained. It is found that the tensile-stress mode of MIAPB improves performance of PN junctions by reconstructing the interface potential barrier and the compressive-stress mode by stimulating strong interaction with the interface barrier. Thus, a tensile-stress MIAPB should be applied inside the interface barrier region and a compressive-stress one outside the interface region. Numerical results show that the maximal output current can be increased by 7.16 times via a tensile-stress MIAPB and 5.18 times via a compressive-stress one, compared to the one without MIAPB, when the doping concentrations are set as 1 × 1021 m-3 with the loading spacing same as the width of the depletion-layer. Obviously, our study possesses referential significance to the mechanical tuning on the performance of piezoelectric PN junctions and piezotronic devices.