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


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: 

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.