The determination of the size and shape of buried InAs/InP quantum dots by transmission electron microscopy

Robertson, M.; Bennett, Craig; Webb, Adam; Corbett, J. M.; Raymond, S.; Poole, Philip J.

doi:10.1016/j.ultramic.2004.12.007

Cited by 17 publications

(17 citation statements)

References 24 publications

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“…In order to solve some of the problems mentioned above, we present a study of the thermal quenching from two samples that contain a single layer of InAs QDs embedded in an InP matrix. Their PL spectra show several well-resolved emission bands, extending from 0.75 to 1.1 eV, that can be associated with families of QDs that differ in height by 1 ML, [21][22][23][24][25][26][27][28] while their PL excitation ͑PLE͒ spectra reveal absorption edges that we associate with QD excited states and WL resonances. The evolution with temperature of the multimodal PL of our samples imposes stringent constraints on a model based on coupled rate equations as it should reproduce the thermal behavior of many peaks with the same set of parameters.…”

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confidence: 93%

Carrier thermal escape in families of InAs/InP self-assembled quantum dots

Gélinas

Lanacer²,

Leonelli³

et al. 2010

Phys. Rev. B

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We investigate the thermal quenching of the multimodal photoluminescence from InAs/InP (001) self-assembled quantum dots. The temperature evolution of the photoluminescence spectra of two samples is followed from 10 K to 300 K. We develop a coupled rate-equation model that includes the effect of carrier thermal escape from a quantum dot to the wetting layer and to the InP matrix, followed by transport, recapture or non-radiative recombination. Our model reproduces the temperature dependence of the emission of each family of quantum dots with a single set of parameters. We find that the main escape mechanism of the carriers confined in the quantum dots is through thermal emission to the wetting layer. The activation energy for this process is found to be close to one-half the energy difference between that of a given family of quantum dots and that of the wetting layer as measured by photoluminescence excitation experiments. This indicates that electron and holes exit the InAs quantum dots as correlated pairs.

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mentioning

confidence: 93%

Carrier thermal escape in families of InAs/InP self-assembled quantum dots

Gélinas

Lanacer²,

Leonelli³

et al. 2010

Phys. Rev. B

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“…InAs/InP quantum dots are known to have a square-based, pyramidal shape, with stepwise, single monolayer (ML) variations in height [10]. Typical behaviour is shown in the emission spectrum of Figure 1(a), where ensemble photoluminescence reveals a modal distribution, reflecting the ML changes in quantum dot height.…”

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confidence: 99%

Optical spectroscopy of single, planar, self‐assembled InAs/InP quantum dots

Kim

Jacques

Lapointe

et al. 2006

Phys. Status Solidi (c)

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We present optical spectra from numerous, single, self-assembled InAs/InP quantum dots. More than 50 individual dots are studied that emit in the 1.1-1.6 µm wavelength range. The dots are of high optical quality as judged by the clean, single exciton emission line at low power, the resolution limited linewidth, and the brightness. Each dot exhibits similar trends in the power evolution spectra, despite large variations in height and diameter. The level splittings in the p-shell increase with decreasing height, which we interpret to be from dot elongation along the [011] direction. The evolution of the spectra with increasing power agrees well with predictions from effective bond orbital calculations.1 Introduction Self-assembled semiconductor quantum dots have been studied extensively because of one's ability to tailor atom-like properties within a solid state medium. Such dots allow one to manipulate its properties via electric, magnetic, and vacuum fields and to perform experiments that demonstrate indistinguishable single photons [1], entangled photon pairs [2] and electro-optical spin storage [3]. To date, the vast majority of studies have utilized InAs/GaAs quantum dots emitting at wavelengths below 1 µm; primarily because of their high optical quality and because of the availability of both optical sources and highly efficient detectors within this wavelength range. Although InAs/GaAs dots have been used to demonstrate longer wavelength emission, a more promising candidate for wavelengths around 1.55 µm, where one finds the attenuation minimum for optical fibre, is the InAs/InP quantum dot system. At the present time, optical studies of single InAs/InP dots have not been as comprehensive as those for InAs/GaAs dots, although reports have addressed the challenges of both wavelength tuning and site selection [4][5][6][7][8]. Of the techniques available for site selection, some may result in exciton linewidth broadening and/or a reduction in signal to noise ratio; making it difficult to extract key intrinsic information such as fine structure, exchange interaction energies, binding energies and excited state structure etc. In addition, directed templating techniques [9] may alter the quantum dot properties as a result of the proximity to free surfaces or the presence of anisotropic piezoelectric potentials. With this in mind, it is necessary to produce a baseline for untemplated, naturally formed Stranski-Krastanow planar dots, from which site-selected dots can be compared. In the work presented here, we study in excess of 50 individual, planar InAs/InP quantum dots, with the aim of establishing the baseline behaviour discussed above. Dots are selected for their high optical quality, as inferred from their brightness and resolution limited linewidth. We compare the observed spectra to previously reported effective bond orbital model calculations [9].

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“…Details of the specimen preparation have been previously published. 25,26 HAADF-STEM imaging was performed at 200 kV using a JEOL JEM-2100 F STEM equipped with a Gatan ADF detector ͑5-11 mm active diameter͒. The inner detector angle of the ADF detector was set to 51 mrad.…”

Section: Methodsmentioning

confidence: 99%

“…7͑a͔͒ are truncated pyramids with flat top and bottom surfaces and 25°side angles, corresponding to ͑113͒ facets, in agreement with previous reports. 26,39,40 Substantial modifications in the QD shape are observed in samples showing intermediate PL changes. For interstitial-mediated intermixing in GID samples the flat top becomes spherical, transforming the truncated pyramid QD into a domelike structure as shown in Fig.…”

Section: Vacancy Trapping In Compressively Strained Inas/inp Qdsmentioning

confidence: 99%

Vacancy-mediated intermixing in InAs/InP(001) quantum dots subjected to ion implantation

Dion

Desjardins

Schiettekatte

et al. 2008

Journal of Applied Physics

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Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Vacancy-mediated intermixing in InAs/InP(001) quantum dots subjected to ion implantation Dion, C.; Desjardins, P.; Schiettekatte, F.; Chicoine, M.; Robertson, M. D.; Shtinkov, N.; Poole, P. J.; Wu, X.; Raymond, S.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=fr L'accès à ce site Web et l'utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D'UTILISER CE SITE WEB. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.Vacancy-mediated intermixing in InAs/InP"001… quantum dots subjected to ion implantation We have investigated the influence of defects emanating from phosphorus implantation damage in the InP capping layer on postgrowth thermally induced intermixing in self-assembled InAs/InP͑001͒ quantum dots ͑QDs͒. Photoluminescence ͑PL͒ spectra from as-grown samples could be described as the superposition of separate PL peaks where each peak corresponded to emission from an ensemble of QDs with a particular height ranging from 4 to 13 ML. Blueshift of up to 270 meV and significant bandwidth broadening were observed in the PL spectra after ion implantation with a fluence of 5 ϫ 10 11 −10 14 cm −2 and subsequent annealing at temperatures ranging from 450 to 600°C. From the analysis of the evolution of the QD peaks upon intermixing, which revealed the coexistence of intact QD PL and a broad PL feature related to heavily intermixed QDs, it was suggested that the bandwidth broadening resulted from spatial inhomogeneity in the compositional intermixing. In order to better understand the mechanism responsible for the ion-implantation-induced intermix...

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The determination of the size and shape of buried InAs/InP quantum dots by transmission electron microscopy

Cited by 17 publications

References 24 publications

Carrier thermal escape in families of InAs/InP self-assembled quantum dots

Carrier thermal escape in families of InAs/InP self-assembled quantum dots

Optical spectroscopy of single, planar, self‐assembled InAs/InP quantum dots

Vacancy-mediated intermixing in InAs/InP(001) quantum dots subjected to ion implantation

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