Pressure-Dependent Optical and Vibrational Properties of Monolayer Molybdenum Disulfide

详细信息    查看全文

• 作者：Avinash P. Nayak ; Tribhuwan Pandey ; Damien Voiry ; Jin Liu ; Samuel T. Moran ; Ankit Sharma ; Cheng Tan ; Chang-Hsiao Chen ; Lain-Jong Li ; Manish Chhowalla ; Jung-Fu Lin ; Abhishek K. Singh ; Deji Akinwande
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：January 14, 2015
• 年：2015
• 卷：15
• 期：1
• 页码：346-353
• 全文大小：553K
• ISSN：1530-6992

文摘

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-MoS₂ (1T鈥? and the monolayer 2H-MoS₂ via a diamond anvil cell (DAC) and density functional theory (DFT) calculations. The direct optical band gap of the monolayer 2H-MoS₂ 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-MoS₂, an overall complex structure鈥損roperty relation due to the rich band structure of MoS₂. Remarkably, the metastable 1T鈥?MoS₂ metallic state remains invariant with pressure, with the J₂, A_1g, and E_2g modes becoming dominant at high pressures. This substantial reversible tunability of the electronic and vibrational properties of the MoS₂ family can be extended to other 2D TMDs. These results present an important advance toward controlling the band structure and optoelectronic properties of monolayer MoS₂ via pressure, which has vital implications for enhanced device applications.