摘要
Controlling the band gap by tuning the lattice structure through pressure engineering is a relatively new route for tailoring the optoelectronic properties of two-dimensional (2D) materials. Here, we investigate the electronic structure and lattice vibrational dynamics of the distorted monolayer 1T-MoS 2 (1T′) and the monolayer 2H-MoS 2 via a diamond anvil cell (DAC) and density functional theory (DFT) calculations. The direct optical band gap of the monolayer 2H-MoS 2 increases by 11.7% from 1.85 to 2.08 eV, which is the highest reported for a 2D transition metal dichalcogenide (TMD) material. DFT calculations reveal a subsequent decrease in the band gap with eventual metallization of the monolayer 2H-MoS 2 , an overall complex structure-property relation due to the rich band structure of MoS 2 . Remarkably, the metastable 1T′-MoS 2 metallic state remains invariant with pressure, with the J 2 , A 1g , and E 2g modes becoming dominant at high pressures. This substantial reversible tunability of the electronic and vibrational properties of the MoS 2 family can be extended to other 2D TMDs. These results present an important advance toward controlling the band structure and optoelectronic properties of monolayer MoS 2 via pressure, which has vital implications for enhanced device applications.