Sensitivity of Reflectance Anisotropy Spectroscopy to the Orientation of Ge Dimers on Vicinal Si(001)

Abstract

Reflectance anisotropy spectroscopy (RAS) is employed to follow the initial room temperature growth of Ge dimer layers on clean vicinal Si(001)-͑1 3 2͒. The experimental data show structure in the region of 2.5 eV which changes sign depending on Ge dimer orientation. Comparison with microscopic calculations for one monolayer and two monolayer Ge coverages reveals excellent agreement with experiment, demonstrating that surface states localized on Ge dimers are responsible for the RA response in the region of 2.5 eV. This provides the first clear and unambiguous proof that a dimer related transition can be responsible for the RAS sensitivity to dimer orientation. [S0031-9007 (98)05779-2]

Ab initio Theory of Second Harmonic Generation from Semiconductor Surfaces and Interfaces

“…Corresponding monohydride surfaces have symmetric dimers. These values agree well with previous findings [47,48], but differ slightly from LDA values. For example, our GGA value of the bulk Si lattice constant slightly exceeds, and our LDA value slightly underestimates, the experimental value.…”

Real-time reflectance-difference spectroscopy of GaAs molecular beam epitaxy homoepitaxial growth

“…It is known that dimerized (001) surfaces of zincblende semiconductors are optically anisotropic. 1 Optical anisotropies have been associated to either the anisotropic response of surface dimers [2][3][4] or to the dimer-induced cubic-symmetry breakdown of the underlying atomic layers. [5][6][7][8] The anisotropic nature of (001) zincblende surfaces prompted the development of polarized-light techniques as optical, non-invasive probes for semiconductor surface characterization.…”

Anisotropic kinetics on growing Ge(0 0 1) surfaces

“…The growing Ge(0 0 1) surface shows alternating (2 Â 1) and (1 Â 2) reconstructions. Since RD response changes its polarity by switching the dimer direction [13], it is likely that the observed oscillations are attributed to periodic variations in the relative (2 Â 1)/(1 Â 2) coverage, similar to the case for Si/Si(0 0 1) homoepitaxy [3,4]. Fig.…”