Impact of PN junction inhomogeneity on the piezoelectric fields of acoustic waves in piezo-semiconductive fibers

Non-uniform mechanical strain can be easily induced at the interface of a piezoelectric semiconductive (PS) PN junction with variable cross sections by using piezoactive acoustic waves, and thus produces a giant piezoelectric field to significantly enhance the piezotronic effect. For revealing the piezotronic performance modulation in the non-uniform PS PN junction, the electromechanical field under a pair of applied end mechanical forces is studied from perspectives of theoretical analysis and numerical simulations. A one-dimensional linearized model for the PS fiber is established, which is applied for the mechanical analysis of a selected profile with the cross section varying in a specific quadratic function. Numerical results indicate that the acoustoelectric fields in the space charge region of the non-uniform PS PN junction are more sensitive to the applied mechanical forces, compared with that of the uniform junction, especially for a heterogeneous PN junction. Furthermore, the current-voltage relations of a necking PS PN junction can be modulated more easily by the end mechanical forces. Both qualitative conclusions and quantitative results can offer guidance for the piezotronic device design.

Automated summary

Non-uniform mechanical strain induced by piezoactive acoustic waves can greatly enhance the piezotronic effect in a non-uniform piezoelectric semiconductive PN junction. The acoustoelectric fields in the space charge region are more sensitive to applied mechanical forces, especially in heterogeneous junctions. The current-voltage relations of a necking junction can be easily modulated by mechanical forces. These findings provide guidance for piezotronic device design.