Exploration work function and optical properties of monolayer SnSe allotropes

The work function and optical properties are investigated with density functional theory for three monolayer SnSe allotropes. The calculated results indicate that the alpha-SnSe, delta-SnSe, epsilon-SnSe are semiconductor with the band gaps of 0.90, 1.25, and 1.50 eV, respectively. Meanwhile, the work function of delta-SnSe is lower than alpha-SnSe and e-SnSe, which indicates that the delta-SnSe can be prepared of photoemission and field emission nanodevices. More importantly, the alpha-SnSe, delta-SnSe, epsilon-SnSe with the large static dielectric constants are 4.22, 5.48, and 3.61, which demonstrate that the three monolayer SnSe allotropes can be fabricated the capacitor. In addition, the static refractive index of delta-SnSe is larger than alpha-SnSe and delta-SnSe. The different optical properties with three monolayer SnSe allotropes reveal that the allotropes can regulate the properties of the materials. Moreover, our researched results show that the three monolayer SnSe allotropes are sufficient for fabrication of optoelectronic nanodevices. (C) 2017 Elsevier Ltd. All rights reserved.