Exploring the electronic and superior piezoelectric properties of two-dimensional PH-SiX materials for high-performance silicon-based devices

The search for advanced two-dimensional materials with exceptional piezoelectric properties has led to the investigation of PH-SiX (X = Cd, Zn, Bi, Ga, and Al) semiconductors, which are compatible with the existing silicon technology. Through first-principles calculations, we reveal that these materials possess superior piezoelectric coefficients, owing to the lack of inversion symmetry and out-of-plane mirror symmetry in PH-SiX. Notably, PH-SiZn exhibits a d11 value of 63.148 pm V-1, which is substantially higher than that of the well-known 2H-MoS2 by a factor of 17. By comparing d31 of PH-SiX, we conclude that the size of d31 is negatively related to the electronegativity difference between Si and X atoms. Furthermore, the strategic application of compressive strain leads to a significant enhancement of piezoelectricity, with PH-SiAl showing a significant improvement of 369.2% in piezoelectricity at 4% compressive strain. The combination of their dynamic, thermodynamic, and mechanical stabilities, along with tunable bandgaps ranging from 0.11 eV to 1.07 eV, positions PH-SiX as compelling materials for the development of next-generation silicon-based devices. PH-SiZn exhibits a d11 value of 63.148 pm V-1, which is higher than that of 2H-MoS2 by a factor of 17. The compressive strain leads to an enhancement of piezoelectricity, with PH-SiAl in an improvement of 369.2% in piezoelectricity at 4% strain.