Surface-stress-induced optical bulk anisotropy

Hingerl, Kurt; Balderas‐Navarro, R. E.; Hilber, Wolfgang; Bonanni, A.; Stifter, David

doi:10.1103/physrevb.62.13048

Cited by 32 publications

(24 citation statements)

References 18 publications

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“…This term has been attributed to bulk states perturbed at critical points (E 1 , E 1 + ∆ 1 ) by the anisotropic strain field produced by surface dimers [36]. When adsorption of metal atoms eliminates dimers, the intensity of the strain field weakens, and the related anisotropy reduces.…”

Section: Resultsmentioning

confidence: 98%

Detection of surface states anisotropies at GaAs(001)(2 × 4) decapped surfaces

Goletti

Emiliani

Schintke

et al. 2005

Physica Status Solidi (b)

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The surface or bulk origin of the optical anisotropies detected by reflectance anisotropy spectroscopy (RAS) at GaAs(001)(2 × 4) surfaces has been extensively investigated in the last years and a quite general agreement has been reached that the dominating character would be bulk-like. Nevertheless, a very recent paper [F. Arciprete et al., Phys. Rev. B 69, 081308(R) (2004)] has again issued the presence of surface states contributions in optical anisotropies, revealing a structure at 2.5 eV due to surface states, in addition to the well known features around 2.9 eV and 4.5 eV related to the bulk critical points E 1 and E 0 ′. We have carried out a new experiment to prove this conclusion by following the changes in the optical anisotropy of a GaAs(001)(2 × 4) surface in the range 2.0 -5.0 eV induced by Ag/Sb-codeposition. The interface Ag/GaAs(001) is known to be not reactive. Due to its surfactant effect, codeposition of Sb leads to a nearly epitaxial growth of the Ag overlayer. We show that at the early stages of deposition (nominally at 0.25 monolayer) an evident modification of the RAS spectrum is detected at 2.5 eV, well below the photon energy (2.9 eV) where bulk-like anisotropies appear. We relate this modification to the disappearance of surface states characteristic of the (2 × 4) reconstruction, in excellent agreement with previous conclusions and experiments.

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Section: Resultsmentioning

confidence: 98%

Detection of surface states anisotropies at GaAs(001)(2 × 4) decapped surfaces

Goletti

Emiliani

Schintke

et al. 2005

Physica Status Solidi (b)

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“…As pointed out before in refs. [5] and [6] surface reconstruction induces a strain field on top of the islands that propagates through several atomic monolayers into the bulk, thus giving rise to a RD response at energies around the bulk critical points, mainly at E 1 and E 1 + ∆ 1 interband transitions. There exist some reports on the measurements of such a strain field.…”

Section: Resultsmentioning

confidence: 99%

“…RD spectroscopy measures the difference in reflectivity between two mutually orthogonal polarizations and thus provides information on semiconductor regions were the cubic symmetry has been broken by the presence of the surface or interface [2]. Although there is not a conclusive explanation on the physical origin for the reconstruction-induced RD spectra, some theoretical and experimental reports have pointed out that the optical anisotropy related to reconstructions comprises at least two components, namely surfaceand bulk-related, corresponding to dimmer resonances and surface strain-induced bulk anisotropy, respectively [3][4][5][6]. Nevertheless, because RD is extremely sensitive to surface conditions, it allows to be used in parallel with standard techniques to assess surface processes during epitaxial growth.…”

Section: Introductionmentioning

confidence: 99%

Surface dynamics during MBE growth of GaAs(001) monitored by in‐situ reflectance difference spectroscopy

Medel‐Ruíz

Balderas‐Navarro

Lastras‐Martínez

2003

phys. stat. sol. (c)

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We have used in-situ reflectance difference spectroscopy to observe changes in GaAs(001) surface reconstructions during homoepitaxy. With a constant As 4 flux of 5×10 -6 Torr and growth rates of 1.1 ML/s, the starting (2×4) surface exhibits a sudden decrease in the RD signal corresponding to a (3×1) reconstruction as simultaneously evidenced by RHEED observations. Furthermore, by varying Ga fluxes so as to control changes in surface reconstructions between c(4×4) and (2×4), we traced reproducible features that lead us to propose a possible physical origin based on strained islands, induced by surface reconstruction, in order to explain the experimental observations. This last assumption was tested by depositing some atomic layers of InGaAs on a (2×4) GaAs (001) where the change in strain is evident.

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“…RD spectroscopy measures the difference in reflectivity between two mutually orthogonal polarizations and thus provides information on semiconductor regions were the cubic symmetry has been broken by the presence of the surface or interface [1]. One important area of application of RDS is the in situ, real time monitoring of the epitaxial growth of zincblende semiconductors, where RDS spectroscopy has been shown to be highly sensitive to changes in surface reconstruction and in general to changes in surface stoichiometry and epilayer morphology during growth [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Model for the strain‐induced reflectance‐difference spectra of InGaAs/GaAs (001) epitaxial layers

Lastras‐Martínez

Balderas‐Navarro

Medel‐Ruíz

et al. 2003

phys. stat. sol. (c)

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We present a model to describe the Reflectance-difference (RD) spectra of InGaAs grown on GaAs (001) at T=500 o C, in the energy range from 2.3-3.5 eV. The model assumes the presence of an orthorhombic strain in the InGaAs epilayer that accounts for an anisotropic process of nucleation of InGaAs islands. We show that the developed model leads to accurate fits to the experimental RD spectra of InGaAs/GaAs for epilayer thickness both below and above of the critical thickness for the 2D-3D growth-mode transition. From the fitting of the theoretical model to the experimental RD line shapes we obtain quantitative information on changes in surface stoichiometry and morphology at the onset of the 2D-3D transition. Our results demonstrate that the RD line shape of InGaAs/GaAs in the 2.3-3.5 eV energy range can be explained entirely in terms of surface-modified InGaAs E 1 and E 1 +∆ 1 bulk transitions with no need to invoke surface states.

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Surface-stress-induced optical bulk anisotropy

Cited by 32 publications

References 18 publications

Detection of surface states anisotropies at GaAs(001)(2 × 4) decapped surfaces

Detection of surface states anisotropies at GaAs(001)(2 × 4) decapped surfaces

Surface dynamics during MBE growth of GaAs(001) monitored by in‐situ reflectance difference spectroscopy

Model for the strain‐induced reflectance‐difference spectra of InGaAs/GaAs (001) epitaxial layers

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