Multiple excitons and the electron–phonon bottleneck in semiconductor quantum dots: An ab initio perspective

Prezhdo, Oleg V.

doi:10.1016/j.cplett.2008.03.099

Cited by 89 publications

(78 citation statements)

References 69 publications

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“…However, because of the magnitude of [ ∂E/∂a ], the evolution of the bandgap as a function of temperature is influenced more by the electron-phonon interaction than by lattice deformation. Since the photogenerated e-h carriers are spatially confined in a small box of NC, the electron-phonon interaction is strengthened, resulting in a larger value of d E g /d T than the values for bulk crystals of semiconductors41. Furthermore, the crystalline lattice of the NC is possibly distorted more than that of a bulk crystal42.…”

Section: Resultsmentioning

confidence: 99%

Origin of the Photoluminescence Quantum Yields Enhanced by Alkane-Termination of Freestanding Silicon Nanocrystals: Temperature-Dependence of Optical Properties

Ghosh

Takeguchi

Nakamura

et al. 2016

Sci Rep

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On the basis of the systematic study on temperature dependence of photoluminescence (PL) properties along with relaxation dynamics we revise a long-accepted mechanism for enhancing absolute PL quantum yields (QYs) of freestanding silicon nanocrystals (ncSi). A hydrogen-terminated ncSi (ncSi:H) of 2.1 nm was prepared by thermal disproportination of (HSiO1.5)n, followed by hydrofluoric etching. Room-temperature PL QY of the ncSi:H increased twentyfold only by hydrosilylation of 1-octadecene (ncSi-OD). A combination of PL spectroscopic measurement from cryogenic to room temperature with structural characterization allows us to link the enhanced PL QYs with the notable difference in surface structure between the ncSi:H and the ncSi-OD. The hydride-terminated surface suffers from the presence of a large amount of nonradiative relaxation channels whereas the passivation with alkyl monolayers suppresses the creation of the nonradiative relaxation channels to yield the high PL QY.

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Section: Resultsmentioning

confidence: 99%

Origin of the Photoluminescence Quantum Yields Enhanced by Alkane-Termination of Freestanding Silicon Nanocrystals: Temperature-Dependence of Optical Properties

Ghosh

Takeguchi

Nakamura

et al. 2016

Sci Rep

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“…The value of dE/dT for NCs is larger than that for bulk Si. Due to a strong spatial confinement in NCs, the electron-phonon interaction becomes strong [27,[37][38].The strong coupling leads to a change in the energy gap as the temperature decreases.…”

Section: Temperature Dependence Of the Pl Energymentioning

confidence: 99%

Influence of Oxidation on Temperature-Dependent Photoluminescence Properties of Hydrogen-Terminated Silicon Nanocrystals

Ghosh

Shirahata

2020

Crystals

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In this study, we investigate temperature-dependent photoluminescence (PL) in three samples of hydrogen-terminated silicon nanocrystals (ncSi-H) with different levels of surface oxidation.ncSi-H was oxidized by exposure to ambient air for 0 h, 24 h, or 48 h. The PL spectra as a function of temperature ranging between room temperature (~297 K) and 4 K are measured to elucidate the underlying physics of the PL spectra influenced by the surface oxidation of ncSi-H. There are striking differences in the evolution of PL spectra according to the surface oxidation level. The PL intensity increases as the temperature decreases. ForncSi-H with a smaller amount of oxide, the PL intensity is nearly saturated at 90 K. In contrast, the PL intensity decreases even below 90 K for the heavilyoxidized ncSi-H. For all the samples, full-width at half maxima (FWHM)decreases as the temperature decreases. The plots of the PL peak energy as a function of temperature can be reproduced with an equation where the average phonon energy and other parameters are calculated.

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“…The current perspective and analysis of the controversies regarding the phonon bottleneck in semiconductor QDs have been discussed by Prezhdo [4]. However, this simple picture fails when the actual dots are probed using advanced local probe techniques that provide excellent spatial and spectral resolutions.…”

Section: Introductionmentioning

confidence: 99%

Effects of crossed states on photoluminescence excitation spectroscopy of InAs quantum dots

Chin-Wen

Lin

et al. 2011

Nanoscale Res Lett

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In this report, the influence of the intrinsic transitions between bound-to-delocalized states (crossed states or quasicontinuous density of electron-hole states) on photoluminescence excitation (PLE) spectra of InAs quantum dots (QDs) was investigated. The InAs QDs were different in size, shape, and number of bound states. Results from the PLE spectroscopy at low temperature and under a high magnetic field (up to 14 T) were compared. Our findings show that the profile of the PLE resonances associated with the bound transitions disintegrated and broadened. This was attributed to the coupling of the localized QD excited states to the crossed states and scattering of longitudinal acoustical (LA) phonons. The degree of spectral linewidth broadening was larger for the excited state in smaller QDs because of the higher crossed joint density of states and scattering rate.

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Multiple excitons and the electron–phonon bottleneck in semiconductor quantum dots: An ab initio perspective

Cited by 89 publications

References 69 publications

Origin of the Photoluminescence Quantum Yields Enhanced by Alkane-Termination of Freestanding Silicon Nanocrystals: Temperature-Dependence of Optical Properties

Origin of the Photoluminescence Quantum Yields Enhanced by Alkane-Termination of Freestanding Silicon Nanocrystals: Temperature-Dependence of Optical Properties

Influence of Oxidation on Temperature-Dependent Photoluminescence Properties of Hydrogen-Terminated Silicon Nanocrystals

Effects of crossed states on photoluminescence excitation spectroscopy of InAs quantum dots

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