Polarization enhanced carrier performance in GaN/WSSe heterostructures for overall water splitting: A first-principles study

• Published in: Applied surface science Vol. 682; p. 161734
• Main Authors: Deng, Da-Wei, Ran, Li-Xiu, Li, Yun-Bo, Ge, Qing-Xia, Xu, Ying, Li, Xi-Bo, Tang, Zhen-Kun, Yin, Wen-Jin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.02.2025
• Subjects: 2D vdW heterostructure; Carrier behavior; Intrinsic polarization; Photocatalytic water splitting; 2D vdW heterostructure; Intrinsic polarization; Photocatalytic water splitting; Carrier behavior
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2024.161734

[Display omitted] •2D GaN/WSSe vdW heterostructures with enhanced photocatalytic water-splitting efficiency via polarization-induced electric field.•Band alignment tunable from type-II to type-III via polarization-induced Stark effect.•Achieved high carrier mobility (∼8601.5 cm2/Vs) and long lifetime (∼6.35 ps)•Thickness-dependent polarization significantly boosts charge transfer and carrier dynamics. Designing low-dimensional photocatalysts with high efficiency has generated substantial interest for clean energy applications, particularly regarding the optimal carrier mobility and lifetime. Here, the structural and electronic properties of two-dimensional heterostructures composed of polar GaN and WSSe were systematically investigated by first-principles calculations. Tunable band alignment can be effectively achieved in GaN/WSSe heterostructures from type-II to type-III through polarization-induced Stark effect. Interestingly, type-II (2L GaN) and type-III (3L GaN) heterostructures in Ga-Se, N-S, and N-Se polarization arrangements exhibit the capability for spontaneous overall photocatalytic water splitting, along with remarkably high charge carrier concentration (∼8.23 × 1011 cm−2), carrier mobility (∼8601.5 cm2/Vs), and extended carrier lifetime (∼6.35 ps) in Ga(3L)-Se-AA-2. This unique behavior arises from the intrinsic polarization of the heterostructures, pumping the electrons from WSSe side to GaN side. These findings not only highlight the significant potential of GaN/WSSe heterostructures as photocatalysts for overall water splitting but also suggest avenues for developing novel polarization-enhanced heterostructures.