Electronic, optical properties and band-gap tunability of monolayer antimony under pressure: A first-principle study

Abstract

Antimonene as monolayer antimony (Sb) and group-V element has been successfully fabricated and recently become an attractive two-dimensional(2D) wide band-gap semiconductor in fields of optoelectronics and nanodevices. In this paper, the electronic band structures and optical properties of the monolayer Sb are studied by first principles. The impact of pressure on the band-gap and dielectric function of the monolayer Sb is intensively investigated. Its band structure and optical properties are compared with the bulk Sb. In addition, we also discussed the phonon spectrum of single layer antimony. Our results show that the monolayer Sb exhibits semiconductor properties with an indirect band-gap of 1.27eV and its band-gap value is tunable by applying pressure. When the pressure is greater than 3 GPa, the monolayer Sb will change from an indirect band-gap semiconductor to a conductor. Further investigation shows that the monolayer Sb will be transformed into a double-layer flat structure above a critical pressure around 3 GPa, so that the band-gap is tuned to be zero. By studying its phonon spectrum, it is found that antimony is relatively stable. It opens an opportunity for device features of the band-gap tunability and semiconductor-to-metal transition by applying mechanical pressure. Furthermore, it can be explored for building 2D optoelectronic and micro/nano-devices with potential applications as sensors and switches by mechanical pressure.