Crystal and band structures of ZnS, MgS, and ZnS-MgS alloys

ZnS-MgS alloys have great potential applications in ultraviolet optoelectronic devices due to their large bandgaps. The structures of ZnS, MgS, and ZnS-MgS alloys are systematically investigated for different compositions and pressures, using first-principles evolutionary simulations. We successfull...

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Bibliographic Details
Published in:Journal of applied physics 2017-06, Vol.121 (23)
Main Authors: Zhao, Changming, Duan, Yifeng, Gao, Jie, Dong, Huafeng
Format: Article
Language:English
Subjects:
Alloy systems
Applied physics
Crystal structure
Energy gap
First principles
Optoelectronic devices
Phase transitions
Zinc sulfide
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Summary:ZnS-MgS alloys have great potential applications in ultraviolet optoelectronic devices due to their large bandgaps. The structures of ZnS, MgS, and ZnS-MgS alloys are systematically investigated for different compositions and pressures, using first-principles evolutionary simulations. We successfully found the experimentally known structures (B1, B3, and Cmcm for ZnS and B1 for MgS) and the novel stable structures (P4/nmm for ZnS and P213 and R 3 ¯ for MgS). The phase-transition pressures are in good agreement with the experimental results. We also predicted the existence of thermodynamically stable ZnS-MgS alloys at high pressures (P4/nmm-MgZnS2, P21/m-MgZn3S4, Pmm2-MgZn7S8, and R3-Mg8ZnS9) with unusual bonding and electronic properties. Furthermore, we revealed that the structures of Zn-rich alloys are constructed by the supercells of metal P4/nmm-ZnS, leading to the abrupt band-gap increase with the increase in Mg concentration, whereas the structures of Mg-rich alloys are based on those of R 3 ¯ - MgS and the bandgap decreases as the Mg concentration further increases.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.4986929