Quantum Confined Electron–Phonon Interaction in Silicon Nanocrystals

Sagar, D. M.; Atkin, Joanna M.; Palomaki, Peter K. B.; Neale, Nathan R.; Blackburn, Jeffrey L.; Johnson, Justin C.; Nozik, Arthur J.; Raschke, Markus B.; Beard, Matthew C.

doi:10.1021/nl503671n

Cited by 58 publications

(76 citation statements)

References 34 publications

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“…4a, the Raman peak of ncSi-OD shifts predictably toward the lower frequencies, and is dominated by a TO peak centered at 509 cm −1 , along with a low-frequency shoulder at 495 cm −1 . The spectrum was not fitted with a Fano line shape59. According to the literature, a Raman shift of 509 cm −1 arises from the ncSi of ~2.1 nm5860.…”

Section: Resultsmentioning

confidence: 98%

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: 98%

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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show abstract

“…Phonon confinement effects were also considered as a potential source of variability through heat treatments. Although the phonon confinement effect can generate an asymmetric Raman profile, the phonon confinement model does not account for the characteristic anti‐resonnance dip found in the Fano profile on the lower‐energy side of the curve (eg, for boron‐doped silicon). All silicon profiles investigated in this work included this anti‐resonance, providing confidence that Fano interference/boron activation is occuring.…”

Section: Resultsmentioning

confidence: 99%

Measuring the effects of heat treatment on SiC/SiC ceramic matrix composites using Raman spectroscopy

et al. 2019

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The evolution of residual stresses found within a silicon carbide/silicon carbide (SiC/SiC) ceramic matrix composite through thermal treatments was investigated using Raman microspectroscopy. Constituent stress states were measured before, during, and after exposures ranging from 900 to 1300°C for varying times between 1 and 60 minutes. Silicon carbide particles in the as‐received condition exhibited average hydrostatic tensile stresses of approximately 300 MPa when measured at room temperature before and after heat treatment. The room temperature Raman profile of the silicon matrix was altered in both shape and location with heat treatment cycles due to increasing activation of boron within the silicon lattice as heat treatment temperatures increased. By accounting for boron activation in the silicon–boron system, little to no permanent change of any constituent stresses were observed, and the silicon matrix subsequently exhibited a complimentary average hydrostatic compressive stress of approximately 300 MPa at room temperature, measured before and after heat treatment. This result builds upon previous literature and offers increased insight into boron activation phenomena measured through Raman spectroscopy methods.

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“…S3 (Supporting Information). The SiNWs present in all the samples, having sizes of the order of Bohr exciton radius (5 nm for Si), show confinement effects and other excellent properties like field emission and thus provide a very good system to study different microscopic phenomenon like electron–phonon interaction (Fano effect) taking place in the low dimensional systems …”

Section: Resultsmentioning

confidence: 99%

Raman spectroscopy for study of interplay between phonon confinement and Fano effect in silicon nanowires

Saxena

Borah

Kumar

et al. 2015

J. Raman Spectrosc.

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A combined effect of doping (type and species) and size on Raman scattering from silicon (Si) nanowires (NWs) has been presented here to study interplay between quantum confinement and Fano effects. The SiNWs prepared from low doping Si wafers show only confinement effect, as evident from the asymmetry in the Raman line‐shape, irrespective of the doping type. On the other hand SiNWs prepared from wafer with high doping shows the presence of electron–phonon interaction in addition to the phonon confinement effect as revealed from the presence of asymmetry and antiresonence in the corresponding Raman spectra. This combined effect induces an extra asymmetry in the lower energy side of Raman peak for n‐type SiNWs whereas the asymmetry flips from lower energy side to the higher energy side of the Raman peak in p‐type SiNWs. Such an interplay can be represented by considering a general Fano‐Raman line‐shape equation to take care of the combined effect in SiNWs. Copyright © 2015 John Wiley & Sons, Ltd.

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Quantum Confined Electron–Phonon Interaction in Silicon Nanocrystals

Cited by 58 publications

References 34 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

Measuring the effects of heat treatment on SiC/SiC ceramic matrix composites using Raman spectroscopy

Raman spectroscopy for study of interplay between phonon confinement and Fano effect in silicon nanowires

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