The piezotronic effect was first discovered in 2006 in piezoelectric ZnO nanowires with n-type conductivity in Wang’s group [13]. Generally, it exists in heterojunction systems with one material being a piezoelectric semiconductor and the other being a metal, a semiconductor, or an electrolyte [42]. When the piezoelectric material is deformed, polarization charges are induced at the junction between two materials, which modify the interfacial band structure and thus the carrier transport, trapping, generation, and recombination processes. In short, piezotronic effect is a change of the interfacial carrier dynamics due to the piezoelectric polarization.