کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5424460 1395825 2009 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Photoemission from α and β phases of the GaAs(0 0 1)-c(4 × 4) surface
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Photoemission from α and β phases of the GaAs(0 0 1)-c(4 × 4) surface
چکیده انگلیسی
We prepared α- and β surface phases of GaAs(0 0 1)-c(4 × 4) reconstruction by molecular beam epitaxy (MBE) using As4 and As2 molecular beams, respectively, and examined them by angle-resolved ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS) with synchrotron radiation as an excitation source. The UPS valence band spectra and the XPS 3d core level data show pronounced differences corresponding to the surface composition and the atomic structure of the two phases, as proposed in the literature. In UPS, the β phase is characterized by an intensive surface state 0.5 eV below the top of the valence band at low photon energy, while an analogous peak in the α phase spectra is missing. The surface state is interpreted in terms of dangling bonds on As dimers. The As3d and Ga3d core level photoelectron lines exhibit phase-specific shapes as well as differences in the number, position and intensity of their deconvoluted components. The location of various atoms in the surface and subsurface layers is discussed; our photoemission results support models of the β phase and the α phase with As-As dimers and Ga-As heterodimers, respectively.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Surface Science - Volume 603, Issue 20, 15 October 2009, Pages 3088-3093
نویسندگان
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