Developed as a semiconducting material with low formation enthalpy and high stability, silicon phosphide has become one of the gold standards in 2D materials. Moreover, its half-metallic spin-polarized state enables it to serve as a robust and practical alternative to black phosphorous in the field of magnetism and spintronics.
Stable two-dimensional semiconductors that can be synthesized by vapor-based methods are of interest in the fields of electronics, optics, and energy. We have investigated SiP as a potential candidate to be synthesized in vapor-based mode for applications in ultra-thin optoelectronics or flexible photovoltaics. We have prepared SiP nanostructures with lateral sizes up to 20 um using chemical vapor transport (CVT) or flux zone growth. We observed that a SiP nanostructure can be grown directly on an SiO2/Si substrate without the need of any additional support layer.
First-principles total energy studies were performed using the electron exchange-correlation functional of density-functional theory, complemented by generalized gradient approximation (GGA). It was found that SiP undergoes an indirect-to-direct gap transition from 1.69 to 2.5 eV. This was accompanied by an improvement in its optical band gap and electrical resistivity. The valence band structure of this new phase was characterized and found to be compatible with the symmetry of the SiP system.
