| H,F修饰单层GeTe的电子结构与光催化性质 |
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| 引用本文： | 方文玉,张鹏程,赵军,康文斌.H,F修饰单层GeTe的电子结构与光催化性质[J].物理学报,2020(5):154-163. |
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| 作者姓名： | 方文玉 张鹏程 赵军 康文斌 |
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| 作者单位： | 湖北医药学院公共卫生与管理学院;湖北省南水北调水源区生物医药研发检测共享平台 |
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| 基金项目： | 国家自然科学基金(批准号:11947006);湖北医药学院人才启动金项目(批准号:2018QDJZR22);湖北省教育厅科学技术研究项目(批准号:B2018434)资助的课题~~ |
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| 摘 要： | 采用基于密度泛函理论的第一性原理平面波赝势方法,计算了单层GeTe、表面氢化及氟化单层GeTe的晶体结构、稳定性、电子结构和光学性质.计算结果表明,经过修饰后, GeTe的晶格常数、键角、键长增大,且均具有较好的稳定性.电子结构分析表明,单层GeTe为间接带隙半导体,全氢化修饰、全氟化修饰以及氢氟共修饰(F, Ge同侧;H, Te同侧)则转变为直接带隙半导体,且修饰后的能隙均不同程度减小.载流子有效质量表明,全氢化、全氟化以及氢氟共修饰GeTe (F, Ge同侧;H, Te同侧)的有效质量减小,其载流子迁移率增强.带边势分析结果显示,单层GeTe能够光裂解水制氢和析氧,而修饰后的GeTe的价带带边势明显下移,其氧化性明显增强,能够光裂解水析O2, H2O2, O3以及OH·等产物.光学性质表明,修饰后的GeTe对可见光区和红、紫外区的光谱吸收效果明显增强,表明其在光催化领域有着广阔的应用前景.
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| 关 键 词： | 单层GeTe 电子结构 有效质量 光催化性能 |
Electronic structure and photocatalytic properties of H,F modified two-dimensional GeTe |
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| Fang Wen-Yu,Zhang Peng-Cheng,Zhao Jun,Kang Wen-Bin.Electronic structure and photocatalytic properties of H,F modified two-dimensional GeTe[J].Acta Physica Sinica,2020(5):154-163. |
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| Authors: | Fang Wen-Yu Zhang Peng-Cheng Zhao Jun Kang Wen-Bin |
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| Affiliation: | (School of Public Health and Management,Hubei University of Medicine,Shiyan 442000,Chin;Hubei Biomedical Detection Sharing Platform in Water Source Area of South to North Water Diversion Project,Shiyan 442000,China) |
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| Abstract: | Using the first principle calculation based on the density functional theory, we have systematically investigated the structure stability, electronic structure and photocatalytic properties of two-dimensional singlelayered GeTe crystal structure modified by H and F. The results show that the lattice constant, bond angle and bond length of GeTe increase after being modified. The stability analysis shows that all the materials have excellent dynamical, mechanical, and thermal stabilities. The electronic structure analysis shows that the twodimensional GeTe is an indirect bandgap semiconductor with an energy gap of 1.797 eV, and its energy band is mainly composed of Ge-4 p and Te-5 p, while it is converted into a direct bandgap semiconductor by H or F modification and H-F co-modification(F and Ge on one side, H and Te on the other), and their corresponding energy gaps are reduced to 1.847 eV(fH-GeTe), 0.113 eV(fF-GeTe) and 1.613 eV(hF-GeTe-hH). However, hHGeTe-hF is still an indirect band gap semiconductor, and its energy gap is reduced to 0.706 eV. The results of the density of states show that part of the Ge-4 p and Te-5 p electrons are transferred to a deeper level due to the adsorption of H or F atoms, resulting in a strong orbital hybridization between them and the adsorbed atoms. The effective mass shows that the effective mass of H or F modified and H-F co-modified GeTe(F and Ge on one side, H and Te on the other) decrease, and their carrier mobilities increase. The carrier recombination rates of all modified GeTe materials are lower than that of the intrinsic GeTe, so the semiconductor will be more durable. The electron density difference shows that due to the electronegativities of atoms being different from each other, when H or F is used to modify GeTe, some electrons transfer to H and F atoms, resulting in the weakening of covalent bond between Ge and Te atoms and the enhancement of ion bond. The results of band-edge potential analysis show that GeTe can produce hydrogen and oxygen by photolysis of water. However, the valence band edge potential of the modified GeTe decreases significantly, and its oxidation ability increases considerably, the photocatalytic water can produce O2, H2, O3, OH·, etc. Optical properties show that the modified GeTe can enhance the absorption of visible and ultraviolet spectrum, which indicates that they have great application prospects in the field of photocatalysis. |
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| Keywords: | two-dimensional GeTe electronic structure effective mass photocatalysis |
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