Janus structures of the C 2h polymorph of gallium monochalcogenides: first-principles examination of Ga 2 XY (X/Y = S, Se, Te) monolayers

• Published in: RSC advances 2023-04, Vol.13 (18), p.12153-12160
• Main Authors: Tran, Tuan-Anh, Hai, Le S, Vi, Vo T T, Nguyen, Cuong Q, Nghiem, Nguyen T, Thao, Le T P, Hieu, Nguyen N
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/D3RA01079A

Group III monochalcogenide compounds can exist in different polymorphs, including the conventional and phases. Since the bulk form of the -group III monochalcogenides has been successfully synthesized [ (2006) 235202], prospects for research on their corresponding monolayers have also been opened. In this study, we design and systematically consider a series of Janus structures formed from the two-dimensional phase of gallium monochalcogenide Ga XY (X/Y = S, Se, Te) using first-principles simulations. It is demonstrated that the Janus Ga XY monolayers are structurally stable and energetically favorable. Ga XY monolayers exhibit high anisotropic mechanical features due to their anisotropic lattice structure. All Janus Ga XY are indirect semiconductors with energy gap values in the range from 1.93 to 2.67 eV. Due to the asymmetrical structure, we can observe distinct vacuum level differences between the two surfaces of the examined Janus structures. Ga XY monolayers have high electron mobility and their carrier mobilities are also highly directionally anisotropic. It is worth noting that the Ga SSe monolayer possesses superior electron mobility, up to 3.22 × 10 cm V s , making it an excellent candidate for potential applications in nanoelectronics and nanooptoelectronics.