Excited states of individual quantum dots studied by photoluminescence spectroscopy

Hessman, Dan; Castrillo, P.; Pistol, Mats‐Erik; Pryor, Craig; Samuelson, Lars

doi:10.1063/1.117879

Cited by 118 publications

(65 citation statements)

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“…Comparison with PL measurements shows good agreement with the major features [13]. PL of single quantum dots shows energies in the range 1.62 − 1.64eV, which corresponds to the calculated energies for island heights in the range 14 − 17 nm.…”

Section: Discussionsupporting

confidence: 76%

“…Although the band diagram shows a pocket below the island, there are no localized states there. The localized valence-band states provide a partial explanation for the observation of multiple lines seen in photoluminescence (PL) [13]. An excited hole that relaxed into a B state would be unable to transfer into one of the A states, and would instead recombine with an electron in its ground state.…”

Section: Electronic Structurementioning

confidence: 99%

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Electronic structure of strainedInP/Ga0.51In
Pryor
¹
,
Pistol
²
,
Samuelson
³

1997
Phys. Rev. B
Self Cite
212
4
130
0
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We calculate the electronic structure of nm scale InP islands embedded in Ga0.51In0.49P. The calculations are done in the envelope approximation and include the effects of strain, piezoelectric polarization, and mixing among 6 valence bands. The electrons are confined within the entire island, while the holes are confined to strain induced pockets. One pocket forms a ring at the bottom of the island near the substrate interface, while the other is above the island in the GaInP. The two sets of hole states are decoupled. Polarization dependent dipole matrix elements are calculated for both types of hole states.

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Section: Discussionsupporting

confidence: 76%

Section: Electronic Structurementioning

confidence: 99%

Electronic structure of strainedInP/Ga0.51In
Pryor
¹
,
Pistol
²
,
Samuelson
³

1997
Phys. Rev. B
Self Cite
212
4
130
0
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show abstract

“…[9][10][11][12]27 For example, a range of single dot line widths over 2 orders of magnitude have been reported for II-VI nanocrystallite QDs. [9][10][11] It has therefore been difficult to use single dot line shapes to learn about the intrinsic physics of these QD systems.…”

mentioning

confidence: 99%

Influence of Spectral Diffusion on the Line Shapes of Single CdSe Nanocrystallite Quantum Dots

1999

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We study the emission line shapes of single CdSe nanocrystallite quantum dots. Single dot line shapes are found to result from rapid spectral shifting of the emission spectrum rather than the intrinsic physics of the quantum dot. A strong dependence of single dot line widths on excitation intensity, wavelength, temperature, and integration time is found and is correlated with the number of times that the quantum dot is excited during the acquisition of a single spectrum. The observed results are consistent with thermally assisted spectral diffusion, activated by the release of excess excitation energy.Recent advances in the detection of single molecules have been responsible for a level of understanding in condensed phase systems that was not previously possible. Of particular interest are incoherent dynamic effects, which can be completely hidden when averaged over an ensemble. In recent years, single chromophore spectroscopy has allowed the direct observation of single enzyme reactions, 1 single energy transfer events, 2 and single molecule rotational dynamics. 3 In addition, new and unexpected physical phenomena have been observed, which appear to be common to many single chromophore systems, such as fluorescence blinking 4-6 and spectral shifting (spectral diffusion). [7][8][9][10][11][12] One field that has greatly benefited from single chromophore spectroscopy is the study of semiconductor quantum dots (QDs). QDs are of great interest due to their unique size dependent optical properties, 13 which can easily be tuned during fabrication. 14 Unfortunately, the characteristics that make QDs interesting also make them inherently difficult to study. Inhomogeneities in size and shape within ensemble samples result in spectral broadening that is many orders of magnitude larger than single QD spectra. 9,15 Though the mechanisms are thought to be quite different, the study of single QDs has revealed phenomena common to other single chromophore systems such as blinking 4 and spectral diffusion. [9][10][11][12] It has also revealed new characteristics specific to QDs such as ultranarrow transition line widths, 9,15 giant Overhauser shifts, 16 multicarrier effects, 17,18 and fluctuating local electric fields. 12 One area of particular interest which can, in principle, be addressed on the single QD level, is the nature of the homogeneous line shape. While theory predicts that QDs should have atomic-like spectral transitions due to long excited-state lifetimes and weak coupling to acoustic phonons, 19 previous ensemble experiments have suggested that line widths in both excitation [20][21][22] and emission 23-25 are quite broad (for example, "homogeneous" line widths extracted from fluorescence line narrowing experiments in CdSe nanocrystallite QDs are reported to be ∼5 meV 26 ). It was expected that single QD spectroscopy would uncover the true "homogeneous" line width. However, while single dot line widths are typically found to be significantly narrower than what is seen in ensemble experiments, many single dot exp...

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“…15 Second, the dot forms in the quantum well under the InP stressor, far from the sample surface and from the sidewalls, so that no surface states and depletion layers affect the recombination. This is not the case in dots that are isolated through a metallic mask, 16 where the Schottky barrier may change the band alignment, or in free-standing dots that are affected by charges at the surface. 17 In Fig.…”

mentioning

confidence: 99%

Effects of few-particle interaction on the atomiclike levels of a single strain-induced quantum dot

et al. 2000

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Excited states of individual quantum dots studied by photoluminescence spectroscopy

Cited by 118 publications

References 1 publication

Electronic structure of strainedInP/Ga0.51In
Pryor
¹
,
Pistol
²
,
Samuelson
³

1997
Phys. Rev. B
Self Cite
212
4
130
0
View full text Add to dashboard Cite

Electronic structure of strainedInP/Ga0.51In
Pryor
¹
,
Pistol
²
,
Samuelson
³

1997
Phys. Rev. B
Self Cite
212
4
130
0
View full text Add to dashboard Cite

Influence of Spectral Diffusion on the Line Shapes of Single CdSe Nanocrystallite Quantum Dots

Effects of few-particle interaction on the atomiclike levels of a single strain-induced quantum dot

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Excited states of individual quantum dots studied by photoluminescence spectroscopy

Cited by 118 publications

References 1 publication

Electronic structure of strainedInP/Ga0.51InPryor1, Pistol2, Samuelson3 1997Phys. Rev. BSelf Cite21241300View full textAdd to dashboardCite

Electronic structure of strainedInP/Ga0.51InPryor1, Pistol2, Samuelson3 1997Phys. Rev. BSelf Cite21241300View full textAdd to dashboardCite

Influence of Spectral Diffusion on the Line Shapes of Single CdSe Nanocrystallite Quantum Dots

Effects of few-particle interaction on the atomiclike levels of a single strain-induced quantum dot

Contact Info

Product

Resources

About

Electronic structure of strainedInP/Ga0.51In
Pryor
¹
,
Pistol
²
,
Samuelson
³

1997
Phys. Rev. B
Self Cite
212
4
130
0
View full text Add to dashboard Cite

Electronic structure of strainedInP/Ga0.51In
Pryor
¹
,
Pistol
²
,
Samuelson
³

1997
Phys. Rev. B
Self Cite
212
4
130
0
View full text Add to dashboard Cite