Surface compositional gradients of InAs∕GaAs quantum dots

Biasiol, G.; Heun, S.; Golinelli, G. B.; Locatelli, Andrea; Menteş, Tevfik Onur; Guo, Fang; Höfer, Christian; Teichert, Christian; Sorba, L.

doi:10.1063/1.2135213

Cited by 31 publications

(35 citation statements)

References 24 publications

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“…The temperature was then lowered to 490 1C, followed by the deposition of 2 nm GaAs at 1 ML/s and 30 s annealing at the same temperature. The sample was then rapidly cooled down and overgrown with a protective layer of As 4 to avoid oxidation of the surface during exposure to air [20].…”

Section: Methodsmentioning

confidence: 99%

Surface compositional mapping of self-assembled InAs/GaAs quantum rings

Biasiol

Magri

Heun

et al. 2009

Journal of Crystal Growth

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Section: Methodsmentioning

confidence: 99%

Surface compositional mapping of self-assembled InAs/GaAs quantum rings

Biasiol

Magri

Heun

et al. 2009

Journal of Crystal Growth

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“…[12]. Biasiol et al have reported the surface compositional gradients around the InAs/GaAs QDs using X-ray photoemission electron microscopy [12].…”

Section: Resultsmentioning

confidence: 99%

“…[12]. Biasiol et al have reported the surface compositional gradients around the InAs/GaAs QDs using X-ray photoemission electron microscopy [12]. According to their results, InAs QDs partially capped with a thin GaAs layer incorporate with GaInAs surrounding structures whose composition of In decreases from the edge of the original QDs to the diffused borders, suggesting the existence of complex nano-structures around the QDs.…”

Section: Resultsmentioning

confidence: 99%

Effects of growth temperature of partial GaAs cap on InAs quantum dots in In‐flush process for single dot spectroscopy

Kumagai

Ohkouchi

Shirane

et al. 2011

Phys. Status Solidi (c)

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We have investigated effects of growth temperature of partial GaAs cap (Tcap) on InAs quantum dots (QDs) in indium‐flush (In‐flush) process with atomic force microscopy (AFM) and micro photoluminescence (μ‐PL) measurements. Tcap in In‐flush process are varied from 385 °C to 485 °C as an experimental parameter. In order to investigate the effects of Tcap on structural property of single InAs QD, shape of QD in initial capping process are characterized by AFM measurements in air at room temperature. While isotropic shape of QDs is kept in low Tcap conditions below about 440 °C, in‐plane anisotropy of initial shape of QDs are increased with increasing of Tcap due to elongation to the [1$ \bar 1 $0] direction. μ‐PL measurements are performed at 7K for the investigation of the effects of Tcap on optical property in single InAs QDs. In low Tcap conditions from 410 °C to 435 °C, distinct emissions from excitonic states in single QDs are observed. In the same Tcap range, the AFM result shows that isotropic shape of QDs is kept. On the other hand, in high Tcap conditions above about 440 °C, indefinite peaks and broad emissions appear remarkably. Excitonic emissions which are observed in low Tcap range are hardly observed in this high Tcap range (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…3 shows the Ga 3d and In 4d photoelectron core level spectra taken from an InAs ／ GaAs sample . 11) During the growth of InAs on GaAs, after the formation of a two-dimensional wetting layer, the growth of islands is observed which is driven by the strain in the growing film due to the lattice mismatch between InAs and GaAs . The inset of Fig.…”

Section: ．Contrast Mechanismsmentioning

confidence: 99%

Nanoscale Imaging and Spectroscopy with XPEEM

Heun

2005

Journal of The Surface Science Society of Japan

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The continuous miniaturization and increasing complexity of the materials used in modern technology requires to have access to chemical composition, electronic structure, magnetization, and fluctuations in these properties at sub-micron and nanometer scales. X-ray photoemission electron microscopy (XPEEM) can provide this information. The recent years have seen a strong increase in XPEEM activities worldwide. This paper reviews the present situation and future developments of XPEEM in combination with synchrotron radiation. In particular, the role of energy filtering, aberration correction, and temporal resolution is discussed. 1．IntroductionX-ray photoelectron spectroscopy (XPS) and the related technique , X-ray absorption spectroscopy (XAS), are powerful tools for the analysis of surfaces, as widely discussed in this issue. In a traditional experimental setup, the spectroscopic signal is obtained from a spot of some 100 µm to millimeters in diameter, and therefore averages over this area. On the other hand, the progress in modern nanotechnology has fueled an evergrowing demand to perform XPS and XAS from areas as small as the smallest building blocks of those nanostructures . This has triggered the development of special instruments which combine spectroscopy and microscopy and allow to perform XPS and XAS with the highest possible lateral resolution of less than 100 nm. 1)More than 10 years ago, two basic, complemetary design principles have been identified to achieve this goal:2) the scanning and the direct imaging type instruments. In the scanning type instruments the photon beam is demagnified, i.e. the X-rays are focused by an optical system (like a Fresnel zone plate or a Schwarzschild objective) on a small spot on the sample. The photoelectrons excited from this area are then collected by a detector. The lateral resolution of the instrument is given by the size of the illuminated area. A surface map can be obtained by scanning the sample relative to the beam. More details of this kind of instruments can be found in the article of T. Munakata in this issue.

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Surface compositional gradients of InAs∕GaAs quantum dots

Cited by 31 publications

References 24 publications

Surface compositional mapping of self-assembled InAs/GaAs quantum rings

Surface compositional mapping of self-assembled InAs/GaAs quantum rings

Effects of growth temperature of partial GaAs cap on InAs quantum dots in In‐flush process for single dot spectroscopy

Nanoscale Imaging and Spectroscopy with XPEEM

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