Surface strain contributions to the lineshapes of reflectance difference spectra for one‐electron and discrete‐exciton transitions

Lastras-Martı́nez, L. F.; Ortega‐Gallegos, J.; Balderas‐Navarro, R. E.; Flores-Camacho, J. M.; Chavira-Rodríguez, M.; Lastras‐Martínez, A.; Cardona, M.

doi:10.1002/pssc.200779112

Cited by 7 publications

(4 citation statements)

References 23 publications

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“…For instance, the roughness and diffusion gradients of As or vacancies introduced during the growth process are in general different for the upper and lower interfaces of each layer. It is known that As vacancies and their gradient distribution through the QW generates an anisotropic strain field at the interfaces [18]. The relative orientation of these fields at the upper and lower interfaces of a QW is rotated by 90 • around the [001] axis, thus leading to optical anisotropies with opposite signs.…”

Section: Modelmentioning

confidence: 99%

Microscopic optical anisotropy of exciton-polaritons in a GaAs-based semiconductor microcavity

et al. 2017

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Exciton-polaritons in semiconductor microcavities are ideal for the study of the exciton-light interaction and its dependence on light polarization. In this work, we report on the optical response and the dependence on polarization of a polariton microcavity using microreflectance anisotropy spectroscopy (μ-RAS) with a spatial resolution of 10.0 × 10.0 μm 2. We have found that, in contrast to optical reflection, the μ-RAS spectra are quite inhomogeneous along the microcavity surface. We demonstrate the existence of microscopic local domains with differences in optical anisotropy of up to 20% within 100 μm. These variations are independent of the detuning between the optical and excitonic resonances, which in our sample is close to 0 meV. The μ-RAS line shape can be understood by using a model based on the anisotropic strain fields induced at the interfaces of the microcavity. The model agrees quite well with the experimental results and allows us to quantify the split of the energy levels of the exciton-polariton branches induced by the local break of symmetry at the microcavity interfaces.

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Section: Modelmentioning

confidence: 99%

Microscopic optical anisotropy of exciton-polaritons in a GaAs-based semiconductor microcavity

et al. 2017

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“…At both n-and p-doped GaAs the electric field of the space charge layer induces a strain that changes the crystal symmetry from cubic to orthorhombic [25][26][27][28][29]34]. The breakdown of the cubic symmetry gives rise to the pronounced LEO oscillation, as described above, which scales linearly with the integrated surface field and has been used as a measure for the SEF [14][15][16][17][18][19]33]. We therefore conclude the increase of the LEO oscillation (Fig.…”

Section: Interpretation and Discussionmentioning

confidence: 95%

“…It was shown that external uniaxial stress can cause a significant modification of the RAS signal around the E 1 , E 1 þ D 1 critical points [29]. Lastras-Martinez et al [28,33] determined the different contributions of the surface roughness and the strain induced by the surface dimers at undoped GaAs samples. In their work the roughness contribution was found to be rather structureless and small compared to the strain contribution.…”

Section: Interpretation and Discussionmentioning

confidence: 99%

Adsorbate‐induced modification of the surface electric field of GaAs (001)‐c(4 × 4) measured via the linear electro‐optic effect

Bruhn

Passmann

Fimland

et al. 2010

Physica Status Solidi (b)

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We have investigated the modification of the surface electric field (SEF) of the GaAs (001)-c(4 Â 4) surface during the adsorption of cyclopentene and 1,4-cyclohexadiene molecules by reflectance anisotropy spectroscopy (RAS) in the spectral range from 1.5 to 5.0 eV. At around 3 eV the RAS line shape originates from the so-called linear electro-optic effect (LEO). The amplitude of the LEO oscillation scales linearly with the SEF within the RAS penetration depth and is thus a measure for it. For the separation of the LEO from the RAS spectra several different methods are described in the literature. Here, we present a modified method which allows the LEO separation in particular for interfaces between GaAs and organic molecules. The results obtained this way show a significant increase of the LEO effect upon molecule adsorption indicating a higher SEF. The observed changes of the surface electronic properties are probably related to a modification of surface strain upon molecule adsorption.

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“…Uniaxial strain lowers the symmetry of the material and can be detected with RAS [67,68]. Interpretation is relatively straightforward where an external stress is applied to the system, but care is required, for example, when measuring the strain induced by a surface reconstruction [69].…”

Section: Nanostructures and Solid-solid Interfacesmentioning

confidence: 99%

Probing surface and interface structure using optics

McGilp

2010

J. Phys.: Condens. Matter

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Optical techniques for probing surface and interface structure are introduced and recent developments in the field are discussed. These techniques offer significant advantages over conventional surface probes: all pressure ranges of gas-condensed matter interfaces are accessible and liquid-liquid, liquid-solid and solid-solid interfaces can be probed, due to the large penetration depth of the optical radiation. Sensitivity and discrimination from the bulk are the two challenges facing optical techniques in probing surface and interface structure. Where instrumental improvements have resulted in enhanced sensitivity, conventional optical techniques can be used to characterize heterogeneous adsorbed layers on a substrate, often with sub-monolayer resolution. Nanoscale lateral resolution is possible using scanning near-field optics. A separate class of techniques, which includes reflection anisotropy spectroscopy, and nonlinear optical probes such as second-harmonic and sum-frequency generation, uses the difference in symmetry between the bulk and the surface or interface to suppress the bulk contribution. A perspective is presented of likely future developments in this rapidly expanding field.

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Surface strain contributions to the lineshapes of reflectance difference spectra for one‐electron and discrete‐exciton transitions

Cited by 7 publications

References 23 publications

Microscopic optical anisotropy of exciton-polaritons in a GaAs-based semiconductor microcavity

Microscopic optical anisotropy of exciton-polaritons in a GaAs-based semiconductor microcavity

Adsorbate‐induced modification of the surface electric field of GaAs (001)‐c(4 × 4) measured via the linear electro‐optic effect

Probing surface and interface structure using optics

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