Stacking patterns and carrier mobilities of GeS bilayer
Fazel Shojaei1, Hong Seok Kang2*
1Department of Chemistry and Bioactive Material Sciences and Research Institute of Physics and Chemistry, Jeonbuk National University, Jeonju, Chonbuk 561-756, Republic of Korea
2Department of Nano and Advanced Materials, College of Engineering, Jeonju University, Hyoja-dong, Wansan-ku, Chonju, Chonbuk 560-759, Republic of Korea
Adv. Mater. Lett., 2018, 9 (3), pp 205-210
Publication Date (Web): May 16, 2018
Copyright © 2019 VBRI Press
Based on the first-principles calculations, we identify four stacking patterns of the GeS bilayer, in which two most stable ones are almost equally stable. The most stable one corresponds to the experimental pattern in bulk GeS. Its interlayer binding is stronger than those in a-phosphorene and graphene, indicating that the material will rather exist in the form of bilayers or multilayers. Our HSE06 band structure calculations show that both patterns are semiconductors with indirect band gaps in the visible region, which are slightly smaller than that of the monolayer. For the monolayer, our refined calculation based on the deformation potential approximation indicates that the electron mobility along the armchair direction amounts to 4.62×104 cm2 V-1s-1, which is ~40 times larger than that of the a-phosphorene. The electron mobility of the bilayer is dependent on the stacking pattern. The most stable pattern is expected to exhibit the mobility of 1.69×104 cm2V-1s-1, which is still ~30 times larger than that of the bilayer a-phosphorene. A detailed comparison of the carrier mobilities suggests that both of the mono- and bi-layer will be useful for n-type electronics.
First-principles calculation, bilayer formation, band gap, stacking pattern, deformation potential method, carrier mobility.