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Enhancement of monolayer SnSe light absorption by strain engineering: A DFT calculation

Authors: 

Tuan V. Vu, Hien D. Tong, Truong Khang Nguyen, Chuong V. Nguyen, A.A. Lavrentyev, O.Y. Khyzhun, B.V. Gabrelian, Hai L. Luong, Khang D. Pham, Phuc Toan Dang, Dat D. Vo*

Source title: 
Chemical Physics, 521: 5-13, 2019 (ISI)
Academic year of acceptance: 
2019-2020
Abstract: 

Strain effects on the electronic and optical properties of monolayer SnSe is studied by APW + lo method in DFT framework. The applied strains cause direct-indirect transition of SnSe band gap which is mainly constructed by s/p hybridization. The armchair 28.png and zigzag 29.png reduce the unstrained band gap of 1.05 eV down to 0 eV at 12% compression, but at 12% tension, the band gap decreases to 0.726–0.804 eV. The band gap always increases under biaxial strain 32.png at 12% compression to 12% tension. We observe an enhancement of real 30.png and imaginary 31.png parts of dielectric function by 14%–30% of magnitude, wider peak distribution to infrared and ultra-violet regions, and appearance of new peaks in the 30.png and 32.png spectrums. As a consequence, the light absorption 33.png is significantly enhanced in the ultra-violet region and the absorption even starts at lower energy at infrared region.