Raman and photoluminescence properties of Ge nanocrystals in silicon oxide matrix

Jie, Y. X.; Wee, Andrew Thye Shen; Huan, C. H. A.; Sun, W.X.; Shen, Zexiang; Chua, Soo-Jin

doi:10.1016/j.mseb.2003.09.037

Cited by 36 publications

(17 citation statements)

References 22 publications

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“…Our observed intense blue band centered at 3.26 eV is not the same as 3.1 eV band emitted under lower energy excitation reported by others [48,49]. Direct exciton radiative recombination responsible for this emission is not possible because the photon-absorption and photoexcitation take place inside the Ge nanoislands [48] and the observed blue emission displays significant size dependence. However, other mechanisms such as defects related luminescent centers in the matrix and interface reaction responsible for the occurrence of the weak peak around ∼2.84 eV.…”

Section: Annealing Temperaturesupporting

confidence: 45%

“…Furthermore, for the longer annealing time the silicon interdiffusion is the main coarsening mechanism that causes decrement in the compressive stress, which shifts the peak to a lower energy value [46,47]. Our observed intense blue band centered at 3.26 eV is not the same as 3.1 eV band emitted under lower energy excitation reported by others [48,49]. Direct exciton radiative recombination responsible for this emission is not possible because the photon-absorption and photoexcitation take place inside the Ge nanoislands [48] and the observed blue emission displays significant size dependence.…”

Section: Annealing Temperaturesupporting

confidence: 41%

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Ge Nanoislands Grown by Radio Frequency Magnetron Sputtering: Comprehensive Investigation of Surface Morphology and Optical Properties

Samavati

Mustafa

Othaman

et al. 2015

Journal of Nanomaterials

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The comprehensive investigation of the effect of growth parameters on structural and optical properties of Si-based single layer Ge nanoislands grown via Stranski-Krastanov mechanism employing radio frequency magnetron sputtering due to its high deposition rate, easy procedure, economical cost, and safety is carried out. The estimated width and height of Ge nanoislands produced by this technique are in the range of ∼8 to ∼30 and ∼2 to 8 nm, respectively. Varieties parameters are manipulated to optimize the surface morphology and structural and optical behavior of Ge nanoislands. The resulted nanoislands are analyzed using various analytical techniques including atomic force microscope, X-ray diffraction, energy dispersive X-ray spectroscopy, room temperature photoluminescence, and Raman spectroscopy. The optimum parameters for growing high quality samples having high number density and homogenous and small size distribution are found to be 400 ∘ C for substrate temperature, 300 sec for deposition time, 10 sccm for Ar flow, and 100 W for radio frequency power. The excellent features of the results suggest that our systematic investigation on the organized growth factors and their effects on surface parameters and photoluminescence emission energy may constitute a basis for the tunable growth of Ge nanoislands (100) nanoislands suitable in nanophotonics.

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Section: Annealing Temperaturesupporting

confidence: 45%

Section: Annealing Temperaturesupporting

confidence: 41%

Ge Nanoislands Grown by Radio Frequency Magnetron Sputtering: Comprehensive Investigation of Surface Morphology and Optical Properties

Samavati

Mustafa

Othaman

et al. 2015

Journal of Nanomaterials

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“…In another study on deposited Ge-doped SiO 2 films, a broad Raman peak at 270 cm 1 , characteristic of amorphousGe, was found, which evolved into an asymmetric sharper peak at 300 cm 1 upon annealing at above 700°C. 109 The nanocrystallite size, estimated from the fitting of the Raman spectra, was found to increase from 4 to 11 nm upon annealing at different temperatures.…”

Section: Monoatomic Systemsmentioning

confidence: 97%

Raman spectroscopy of optical phonon confinement in nanostructured materials

Arora

Rajalakshmi

Ravindran

et al. 2007

J Raman Spectroscopy

362

294

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If the medium surrounding a nano-grain does not support the vibrational wavenumbers of a material, the optical and acoustic phonons get confined within the grain of the nanostructured material. This leads to interesting changes in the vibrational spectrum of the nanostructured material as compared to that of the bulk. Absence of periodicity beyond the particle dimension relaxes the zone-centre optical phonon selection rule, causing the Raman spectrum to have contributions also from phonons away from the Brillouin-zone centre. Theoretical models and calculations suggest that the confinement results in asymmetric broadening and shift of the optical phonon Raman line, the magnitude of which depends on the widths of the corresponding phonon dispersion curves. This has been confirmed for zinc oxide nanoparticles. Microscopic lattice dynamical calculations of the phonon amplitude and Raman spectra using the bond-polarizability model suggest a power-law dependence of the peak-shift on the particle size. This article reviews recent results on the Raman spectroscopic investigations of optical phonon confinement in several nanocrystalline semiconductor and ceramic/dielectric materials, including those in selenium, cadmium sulphide, zinc oxide, thorium oxide, and nano-diamond. Resonance Raman scattering from confined optical phonons is also discussed.

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“…This shift can be attributed to the quantum confinement effect, which was also observed from Ge nanocrystals embedded in SiO2 matrix. 26) The mean grain size of Ge nanoparticles can be estimated by the peak shift from D = 2π(B/Δω) 1/2 , where, B ≈ 2.0 cm -1 ·nm 2 , Δω is the peak shift compared with that of the cubic Ge. The average size of Ge nanoparticles increased from 1.95 to 8.87 nm corresponding to the reduction temperature from 500°C to 700°C.…”

Section: Mullite Composite Powders Containing Photoluminescent Ge Nanmentioning

confidence: 99%

Preparation of functional metal nanoparticles embedded mullite composite powders by solid solution reduction

Wang

Gao

Wang

et al. 2009

J. Ceram. Soc. Japan

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The mullite composite powders with embedded Fe and Ge nanoparticles were individually prepared through the reduction of Al5.4Fe0.6Si2O13 and Al12Si3.75Ge0.25O26 solid solution. The complete reduction of Fe 3+ cation in solid solution is realized by hydrogen at 1200°C for 1 h. The magnetic properties of composite powders such as hysteresis loops and magnetization versus temperature were measured using SQUID. The Fe nanoparticles with the particle size around 10 nm embedded in mullite grain show the superparamagnetic behavior with the blocking temperature around 50 K. The mullite composite powders with Ge nanoparticles have strong room temperature photoluminescence (PL) at 561, 610, 676, 713 and 787 nm, respectively. The highest photoluminescence intensity was observed in the sample reduced at 500°C for 3 h. Based on the analysis of XPS and Raman spectra, it is clear that the PL phenomenon is derived from the formation of embedded Ge clusters with the average size of around 1-2 nm in mullite composite powders. It is proved that the multi-functional mullite nanocomposites with functional metal nanoparticles can be prepared through the selective reduction of designed solid solutions.

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Raman and photoluminescence properties of Ge nanocrystals in silicon oxide matrix

Cited by 36 publications

References 22 publications

Ge Nanoislands Grown by Radio Frequency Magnetron Sputtering: Comprehensive Investigation of Surface Morphology and Optical Properties

Ge Nanoislands Grown by Radio Frequency Magnetron Sputtering: Comprehensive Investigation of Surface Morphology and Optical Properties

Raman spectroscopy of optical phonon confinement in nanostructured materials

Preparation of functional metal nanoparticles embedded mullite composite powders by solid solution reduction

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