Growth and characterization of site‐selective quantum dots

Helfrich, Mathieu; Schroth, Philipp; Grigoriev, D.; Lazarev, Sergey; Felici, Roberto; Slobodskyy, T.; Baumbach, Tilo; Schaadt, D. M.

doi:10.1002/pssa.201228423

Cited by 7 publications

(8 citation statements)

References 49 publications

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“…The position of a disk in the model, with given a || , above the GaAs surface can be estimated from the exit angle plots 19 20 of the Mythen detector. Figure 5(a,b) show the exit angle plots [in (400) GID geometry] corresponding to different in-plane lattice parameters (as indicated) for the high and low density regions respectively for sample w0795.…”

Section: Resultsmentioning

confidence: 99%

“…3(a,b) ] show intensity variation with respect to α f and a || . From the position of the first maximum ( α f max ), the height ‘z’ above GaAs surface corresponding to any a || can be calculated as 19 20 :…”

Section: Resultsmentioning

confidence: 99%

“…Here we show that composition and strain profile and also PL property of QD can be tuned by controlling the in-plane density of QD by having a growth temperature gradient over the substrate. Results of grazing incidence x-ray scattering (GIXS) 19 20 21 measurements of three representative samples presented here show that composition and morphology across the height of an average QD are quite different in the low-density and in the high-density regions (refer Fig. 1 ).…”

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confidence: 87%

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Density dependent composition of InAs quantum dots extracted from grazing incidence x-ray diffraction measurements

Sharma

Sanyal

Farrer

et al. 2015

Sci Rep

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Epitaxial InAs quantum dots grown on GaAs substrate are being used in several applications ranging from quantum communications to solar cells. The growth mechanism of these dots also helps us to explore fundamental aspects of self-organized processes. Here we show that composition and strain profile of the quantum dots can be tuned by controlling in-plane density of the dots over the substrate with the help of substrate-temperature profile. The compositional profile extracted from grazing incidence x-ray measurements show substantial amount of inter-diffusion of Ga and In within the QD as a function of height in the low-density region giving rise to higher variation of lattice parameters. The QDs grown with high in-plane density show much less spread in lattice parameter giving almost flat density of In over the entire height of an average QD and much narrower photoluminescence (PL) line. The results have been verified with three different amounts of In deposition giving systematic variation of the In composition as a function of average quantum dot height and average energy of PL emission.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 87%

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Density dependent composition of InAs quantum dots extracted from grazing incidence x-ray diffraction measurements

Sharma

Sanyal

Farrer

et al. 2015

Sci Rep

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“…However, there are many problems in previous studies about QDCF. [2][3][4][5] First of all, it is difficult for QDs to keep high efficiency in QDCF film especially QDCF with high concentration of QDs because of its poor dispersion in resin. On the other hand, the luminance of QDCF film is also hard to improve.…”

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confidence: 99%

P-92: Fabrication and Patterning of a Wide-Color-Gamut Color Filter Based on Quantum Dots

Zhou

Zhang

et al. 2016

SID Symposium Digest of Technical Papers

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The patterned color filter films with high concentration quantum dots (QD) were fabricated and proved to be applied as color converting film of white or blue OLEDs and replacement of color filter in LCD. QDs were dispersed in mass production color filter resin, and the quenching of QDs were effectively restrained. Author KeywordsQuantum dots; Color filter; Color gamut Objective and BackgroundWith the development of display technology, wider color gamut and greater color saturation become a hot investigative emphasis. The emission spectrum of backlight and the transmission spectrum of color filter are two important limited factors in display today. Quantum dots are currently applied to display as their narrow photoluminescence peak and tunable peek wavelength. There are two kinds of application of QDs: one is used as backlight brightness enhancement film, and the other as color filter used in white or blue OLEDs and LCD. Backlight brightness enhancement film with QDs have been coming to market which is famous for its ability to efficiently express 50% wider color gamut than the conventional LCD (~115% NTSC in QD films compared to ~87% NTSC in conventional LCD).[1] Compared to QD Backlight brightness enhancement film, QD color filter (QDCF) expect to reach wider color gamut theoretically since it is possible to reduce the mixed color and improve the color purity. However, there are many problems in previous studies about QDCF. [2][3][4][5] First of all, it is difficult for QDs to keep high efficiency in QDCF film especially QDCF with high concentration of QDs because of its poor dispersion in resin. On the other hand, the luminance of QDCF film is also hard to improve. At last, there is only a little margin in the thickness of CF film in mass production. In our opinion, there are four key factors which affect the luminance of QDCF film: 1) the dispersion of QDs in CF resin; 2) the concentration of QDs in QDCF film; 3) the thickness of QDCF film; 4) quenching of QD during the photo process. So in this work we focus on enhancing the dispersion of QDCF film, increasing the concentration of QD and reducing the quenching of QD at a fixed thickness of QDCF film. We dispersed QDs into mass production CF resin, and the QDCF film could patterning with photo process. In addition to this, we also devoted to enhancing the luminance of QDCF resin. Results Dispersion of QDs in color filter resin (QDCF resin)In this experiment, we used the CdSe/ZnS core/shell QDs, including red QD and green QD, and we chose a mass production CF resin without pigment which used acrylic resin as main polymer, propylene glycol monomethyl acetate (PMA) as solvent. The QD content was characterized by QD solid concentration, which is given by equation as follows: QD solid concentration=m(QD)/[m(QD)+m(solid of CF resin)]Using a conventional method, solid QD was added to CF resin and then dispersed QD with magnetic stirring and ultrasonication. The QDs were severely agglomerated when the QD solid concentration was greater than 3%. So we discovere...

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“…Great success has been achieved with nanometer‐sized holes patterned on planar substrate surfaces through which single QDs can be positioned with close to 50 nm precision to target coordinates – for example the center of micro‐pillar cavities. As shown in the papers by Schneider et al 1 and Helfrich et al 2, problems of reduced QD nucleation probability at such holes and degraded QD emission characteristics can be overcome using proper preparation technologies and growth recipes.…”

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confidence: 99%

Site‐selective growth of single quantum dots

Strittmatter¹

2012

Physica Status Solidi (a)

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Growth and characterization of site‐selective quantum dots

Cited by 7 publications

References 49 publications

Density dependent composition of InAs quantum dots extracted from grazing incidence x-ray diffraction measurements

Density dependent composition of InAs quantum dots extracted from grazing incidence x-ray diffraction measurements

P-92: Fabrication and Patterning of a Wide-Color-Gamut Color Filter Based on Quantum Dots

Site‐selective growth of single quantum dots

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