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采用基于密度泛函理论的第一性原理方法和平板模型研究了乙炔和乙烯分子在Ge(001)表面的吸附构型和电子结构.通过系统考察一系列可能存在的吸附方式,结果表明,在0.5monolayer(ML)覆盖度时,两种分子的di-σ吸附构型最为稳定;在覆盖度为1.0ML时的最稳定吸附方式是pairedend-bridge构型.能带结构分析结果可知,吸附构型以及吸附分子的覆盖度均对Ge(001)表面带隙有较大影响,其原因在于费米能级附近的能带主要来自表面二聚体的Ge原子,它们与表面Ge原子的配位环境密切相关,而后者又取决于分子的吸附方式和覆盖度.对于相同的吸附方式,乙烯和乙炔分子具有类似的吸附行为和电子结构.此外,还进一步与Si(001)表面的研究结果进行对比.
Adsorption configuration and electronic structure of acetylene and ethylene on Ge (001) surface were investigated by the first-principles method based on density functional theory and plate model. A series of possible adsorption modes were investigated systematically. The results showed that When the coverage of 0.5monolayer (ML) is reached, the di-σ adsorption configurations of the two molecules are the most stable, and the most stable adsorption mode at the coverage of 1.0ML is the pairedend-bridge configuration.The energy band structure analysis results show that the adsorption structure And the coverage of the adsorbed molecules all have a great influence on the bandgap of Ge (001) because the energy band near the Fermi level mainly comes from the surface dimer Ge atoms, and their coordination with the surface Ge atoms Which is closely related to the environment, which in turn depends on the mode of adsorption and the coverage of the molecule. For the same adsorption mode, the ethylene and acetylene molecules have similar adsorption behavior and electronic structure. In addition, the results of the Si (001) Compared.