Tunable optical and electronic properties of Janus monolayers Ga2SSe, Ga2STe, and Ga2SeTe as promising candidates for ultraviolet photodetectors applications

• Published in: Superlattices and microstructures Vol. 125; pp. 1 - 7
• Main Authors: Bui, Hoi D., Jappor, Hamad Rahman, Hieu, Nguyen N.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2019
• Subjects: Electronic and optical properties; Janus Ga2STe, Ga2STe, and Ga2SeTe monolayers; Photovoltaic absorbers; UV detectors; Photovoltaic absorbers; Janus Ga2STe, Ga2STe, and Ga2SeTe monolayers; UV detectors; Electronic and optical properties
• ISSN: 0749-6036; 1096-3677
• DOI: 10.1016/j.spmi.2018.10.020

Janus Ga2STe, Ga2STe, and Ga2SeTe monolayers have been designed composed of GaS, GaSe, and GaTe monolayers and study their electronic and optical properties using the density functional theory. Interestingly, our results revealed that the Ga2STe and Ga2SeTe have desirable direct band gaps of 0.90 and 1.21 eV, respectively, while Ga2STe has an indirect gap of 2.02 eV, all of the energy bandgaps are smaller than those of the perfect monolayers. The optical absorption confirms a strong absorption of the light in the range between 3 and 21 eV. More importantly, the optical absorption of Janus structures begins in the visible region with absorption coefficients larger than 104 cm−1. Combining the optical and electronic properties, Ga2STe, Ga2STe, and Ga2SeTe monolayers have a great possibility to be used as ultraviolet detectors and photovoltaic absorbers applications. Consequently, the present work offers significant guidelines for the design of optoelectronic devices that made of layered Janus structures and provides useful guidance for further expanding the practical application range of these materials. [Display omitted] •Janus Ga2SSe, Ga2STe, and Ga2SeTe monolayers have desirable direct band gaps of 0.90 and 1.21 eV, respectively.•Janus Ga2SSe, Ga2STe, and Ga2SeTe monolayers have a variety of extraordinary optical properties.•The optical absorption of Janus structures begins in the visible region with absorption coefficients larger than 104 cm−1.•The optical properties of Ga2SSe, Ga2STe and Ga2SeTe monolayers located in UV range.•Janus monolayers can be used as a promising material in the ultraviolet detectors and optoelectronic applications.