In this paper, a new GaSe/ZnS van der Waals heterostructure (vdWH) was constructed and a systematic analysis of the electronic structure, interfacial properties, and transport and photocatalytic capacity of the GaSe/ZnS vdWH was performed by using first-principles calculations. It was found that the heterostructure exhibited excellent photocatalytic performance for water splitting. The direct band gap of the heterostructure calculated using the hybrid HSE06 functional was 2.19 eV, which had a good visible light absorption ability. The electronic structure of the type-II band arrangement effectively reduced the recombination of electron–hole pairs. The heterostructure also showed excellent transport ability, and the carrier mobility of electrons and holes along different directions was greatly improved. Additionally, as the electric field strength increased, the band gap width of the GaSe/ZnS vdWH narrowed and the heterostructure characteristics transitioned from semiconductor to metal properties, which were attributed to the appearance of near-free electronic (NFE) states induced by the strong electric field. Meanwhile, the optical absorption capacity of the heterostructure was greatly improved compared to the ZnS monolayer, reaching 1.44 × 10⁵ cm⁻¹ at an incident photon energy of 8.65 eV. Therefore, the GaSe/ZnS vdWH was proved to be an excellent photocatalytic material for water splitting in the present study.

中文翻译：

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II 型 GaSe/ZnS 异质结构作为光催化剂的载流子迁移率和光学特性：第一原理研究

本文构建了一种新型GaSe/ZnS范德华异质结（vdWH），并利用第一性原理计算对GaSe/ZnS vdWH的电子结构、界面性质、输运和光催化能力进行了系统分析。研究发现，该异质结构表现出优异的光催化水分解性能。利用杂化HSE06泛函计算得到的异质结构的直接带隙为2.19 eV，具有良好的可见光吸收能力。 II型能带排列的电子结构有效地减少了电子-空穴对的复合。该异质结构还表现出优异的传输能力，电子和空穴沿不同方向的载流子迁移率得到了极大的提高。此外，随着电场强度的增加，GaSe/ZnS vdWH的带隙宽度变窄，异质结构特性从半导体性质转变为金属性质，这归因于强电场诱导的近自由电子（NFE）态的出现。电场。同时，与ZnS单层相比，异质结构的光吸收能力大大提高，在入射光子能量为8.65 eV时达到1.44×10 ⁵ cm ^-1 。因此，本研究证明GaSe/ZnS vdWH是一种优异的光催化水分解材料。