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Two-dimensional Hf2CO2/GaN van der Waals heterostructure for overall water splitting: a density functional theory study.

Authors :
Zhang, Minghui
Si, Ruihao
Wu, Xiaoyi
Dong, Yao
Fu, Kun
Xu, Xuewen
Zhang, Jun
Li, Lanlan
Guo, Yue
Source :
Journal of Materials Science: Materials in Electronics; Jul2021, Vol. 32 Issue 14, p19368-19379, 12p
Publication Year :
2021

Abstract

Designing two-dimensional heterojunction with an appropriate band structure is a promising route to search new photocatalyst toward overall water splitting. In the present work, the Hf<subscript>2</subscript>CO<subscript>2</subscript> monolayer was integrated with planar and buckled GaN monolayer to construct the Hf<subscript>2</subscript>CO<subscript>2</subscript>/GaN heterostructures. We then performed a systematic investigation on the stability, electronic structure and carrier mobility of the Hf<subscript>2</subscript>CO<subscript>2</subscript>/GaN heterostructures based on the density functional theory. Due to the negative formation energy and positive frequency modes in phonon dispersion spectra, the designed Hf<subscript>2</subscript>CO<subscript>2</subscript>/GaN–C′B′, Hf<subscript>2</subscript>CO<subscript>2</subscript>/GaNH<subscript>2</subscript>–C′A′ and Hf<subscript>2</subscript>CO<subscript>2</subscript>/GaNH<subscript>2</subscript>–A′C′ are energetically stable. The Hf<subscript>2</subscript>CO<subscript>2</subscript>/GaN–C′B′ and Hf<subscript>2</subscript>CO<subscript>2</subscript>/GaNH<subscript>2</subscript>–C′A′ heterostructures have the suitable band structures which satisfy the requirements of photocatalytic water splitting. The VBM and CBM of the stable heterostructures are completely dominated by GaN (GaNH<subscript>2</subscript>) layer and Hf<subscript>2</subscript>CO<subscript>2</subscript> layer, respectively, which is beneficial to the spatial separation of photogenerated hole and electron. With comparison to GaN monolayer, the designed heterostructures exhibit enhanced response to both visible and ultraviolet light. The electron mobilities of Hf<subscript>2</subscript>CO<subscript>2</subscript>/GaNH<subscript>2</subscript> heterostructures are as high as ~ 2 × 10<superscript>4</superscript> cm<superscript>2</superscript> V<superscript>− 1</superscript> s<superscript>− 1</superscript>. The Hf<subscript>2</subscript>CO<subscript>2</subscript>/GaN heterostructures can be considered as the potential candidates for the applications of both photocatalytic water splitting and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
09574522
Volume :
32
Issue :
14
Database :
Complementary Index
Journal :
Journal of Materials Science: Materials in Electronics
Publication Type :
Academic Journal
Accession number :
151542666
Full Text :
https://doi.org/10.1007/s10854-021-06454-9