Surface energetics and structure of the Ge wetting layer on Si(100)

Article

关键词: ABINITIO MOLECULAR-DYNAMICS;    TOTAL-ENERGY CALCULATIONS;    DIMER-VACANCY LINES;    WAVE BASIS-SET;    ISLAND FORMATION;    COVERED SI(001);    SPECIAL POINTS;    THIN-FILMS;    GROWTH;    STRESS;   

DOI  :  10.1103/PhysRevB.70.205337

来源: SCIE

【 摘 要 】

Ge deposited on Si(100) initially forms heteroepitaxial layers, which grow to a critical thickness of similar to3 MLs before the appearance of three-dimensional strain relieving structures. Experimental observations reveal that the surface structure of this Ge wetting layer is a dimer vacancy line (DVL) superstructure of the unstrained Ge(100) dimer reconstruction. In the following, the results of first-principles calculations of the thickness dependence of the wetting layer surface excess energy for the c(4x2) and 4x6 DVL surface reconstructions are reported. These results predict a wetting layer critical thickness of similar to3 MLs, which is largely unaffected by the presence of dimer vacancy lines. The 4x6 DVL reconstruction is found to be thermodynamically stable with respect to the c(4x2) structure for wetting layers at least 2 ML thick. A strong correlation between the fraction of total surface induced deformation present in the substrate and the thickness dependence of wetting layer surface energy is also shown.

【 授权许可】

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