Theory of size-dependent resonance Raman intensities in InP nanocrystals

Shiang, J. J.; Wolters, R. H.; Heath, James R.

doi:10.1063/1.474031

Cited by 30 publications

(26 citation statements)

References 46 publications

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“…13a is an increase in the LO/TO ratio with increasing Sb composition, which we attribute to the increase in NW diameter. A strong dependence of LO and TO mode intensities on nano-crystallite size (R) has been reported 43 . The phonon mode contributions to the decay rate of the phase relaxation of the excited states of the phonons impacting the LO/TO intensity ratio is predicted to vary as 1/R 2.5 , which explains the observed higher LO/TO ratio with Sb composition in NWs of larger diameter.…”

Section: Resultsmentioning

confidence: 97%

A Two-Step Growth Pathway for High Sb Incorporation in GaAsSb Nanowires in the Telecommunication Wavelength Range

Ahmad

Karim

Hafiz

et al. 2017

Sci Rep

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Self-catalyzed growth of axial GaAs1−xSbx nanowire (NW) arrays with bandgap tuning corresponding to the telecommunication wavelength of 1.3 µm poses a challenge, as the growth mechanism for axial configuration is primarily thermodynamically driven by the vapor-liquid-solid growth process. A systematic study carried out on the effects of group V/III beam equivalent (BEP) ratios and substrate temperature (Tsub) on the chemical composition in NWs and NW density revealed the efficacy of a two-step growth temperature sequence (initiating the growth at relatively higher Tsub = 620 °C and then continuing the growth at lower Tsub) as a promising approach for obtaining high-density NWs at higher Sb compositions. The dependence of the Sb composition in the NWs on the growth parameters investigated has been explained by an analytical relationship between the effective vapor composition and NW composition using relevant kinetic parameters. A two-step growth approach along with a gradual variation in Ga-BEP for offsetting the consumption of the droplets has been explored to realize long NWs with homogeneous Sb composition up to 34 at.% and photoluminescence emission reaching 1.3 µm at room temperature.

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Section: Resultsmentioning

confidence: 97%

A Two-Step Growth Pathway for High Sb Incorporation in GaAsSb Nanowires in the Telecommunication Wavelength Range

Ahmad

Karim

Hafiz

et al. 2017

Sci Rep

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“…However, the optical deformation potential generates Raman intensity by coupling the components of the valence band, 58,59 and the valence band fine structure is should be strongly dependent on QD size and crystal structure (wurtzite vs. zinc blende). 60 In contrast, the resonance Raman-determined EPCs are nearly independent of these properties.…”

Section: Figure 7 Experimental (Black) and Calculated (Red) Frequencmentioning

confidence: 99%

Electron–Phonon Coupling in CdSe/CdS Core/Shell Quantum Dots

et al. 2015

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Resonance Raman spectra and excitation profiles have been measured and semiquantitatively modeled for core/shell quantum dots consisting of 2.7 nm diameter zincblende CdSe cores and thin (0.5 nm) or thick (1.6 nm) CdS shells. The Raman spectra show previously reported trends of increased peak frequency for both the CdSe and the CdS longitudinal optical (LO) phonons with increasing shell thickness. We also find a strong dependence of the peak CdS frequency on excitation energy and a large discrepancy between the experimental frequency of the CdSe+CdS combination band and the sum of the corresponding fundamental frequencies. This suggests that the dominant transitions at high excitation energies are localized on either the CdSe core or the CdS shell and thereby cannot enhance combination band transitions between core and shell. The CdS to CdSe Raman intensity ratios at high excitation energies further support this picture. The electron-phonon coupling for the CdSe LO phonon in the lowest excitonic transition is slightly weaker in the core/shell structures than in pure CdSe quantum dots, contrary to expectations for the Fröhlich coupling mechanism. Possible explanations for this discrepancy are discussed.

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“…For its sensitivity to the structure change, Raman spectroscopy has been used to investigate the structures of porous InP [13,16], InP quantum dots [17], InP nanocrystals [18] and passivated InP [19] etc. Intensification of Raman signals from the porous InP, which is up to 20−25 times more than that of the bulk InP, was observed by Liu et al…”

Section: Introductionmentioning

confidence: 99%

Annealing effect on InP vertical porous arrays

Liu

et al. 2010

Sci. China Technol. Sci.

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InP vertical porous arrays were produced using electrochemical etching at room temperature. The as-etched InP samples were annealed in an ultra high vacuum camber. Cross-sectional analysis of the porous layer was conducted using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Annealing in vacuum was found to meliorate the structural quality of the porous layer. EDX results showed the composition change of the porous InP. By controlling the annealing process parameters, the content ratio of phosphorus (P) to indium (In) is tuneable. Raman property of the samples was also investigated at room temperature. Compared with the sample without annealing treatment, Raman spectrum from the annealed sample showed red-shifted LO and TO peaks together with sharpened LO peak and shortened TO peak. InP vertical porous arrays, annealing effect, Raman property, electrochemical etching Citation:Su G, Liu T Z, Liu W, et al. Annealing effect on InP vertical porous arrays.

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Theory of size-dependent resonance Raman intensities in InP nanocrystals

Cited by 30 publications

References 46 publications

A Two-Step Growth Pathway for High Sb Incorporation in GaAsSb Nanowires in the Telecommunication Wavelength Range

A Two-Step Growth Pathway for High Sb Incorporation in GaAsSb Nanowires in the Telecommunication Wavelength Range

Electron–Phonon Coupling in CdSe/CdS Core/Shell Quantum Dots

Annealing effect on InP vertical porous arrays

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