Advances in piezotronics and piezo-phototronics of two-dimensional semiconductor materials

High-performance electronics and optoelectronics play vital roles in modern society, as they are the fundamental building blocks of functional devices and systems. Two-dimensional semiconductor materials (2D-SCMs) are potential candidates for high-performance electronics and optoelectronics due to their excellent physical, chemical, electrical, and photonic properties. Owing to their special crystalline structure, they also present unique piezoelectricity, which opens a new door to the innovative fields of piezotronics and piezo-phototronics. Piezotronics and piezo-phototronics utilize the piezoelectric polarization charges produced when the 2D-SCMs undergo externally applied strains/stresses to modulate the performance of 2D-SCMs-based electronics and optoelectronics. In this review, firstly, the growth methods and piezoelectric properties of 2D-SCMs are stated, and the mechanisms of piezotronics and piezo-phototronics are also introduced. Afterwards, the recent progress of piezotronics and piezo-phototronics in high-performance 2D-SMCs-based electronics and optoelectronics are systematically reviewed. In addition, the functional devices and systems based on the piezotronics and piezo-phototronics in 2D-SMCs have been summarized. Finally, the research progresses are summarized, and future perspectives are proposed.