Light Emission from Rare-Earth Doped Silicon Nanostructures

Rare earth (Tb or Ce)-doped silicon oxides were deposited by electron cyclotron resonance plasma-enhanced chemical vapour deposition (ECR-PECVD). Silicon nanocrystals (Si-ncs) were formed in the silicon-rich films during certain annealing processes. Photoluminescence (PL) properties of the films were found to be highly dependent on the deposition parameters and annealing conditions. We propose that the presence of a novel sensitizer in the Tb-doped oxygen-rich films is responsible for the indirect excitation of the Tb emission, while in the Tb-doped silicon-rich films the Tb emission is excited by the Si-ncs through an exciton-mediated energy transfer. In the Ce-doped oxygen-rich films, an abrupt increase of the Ce emission intensity was observed after annealing at 1200∘C. This effect is tentatively attributed to the formation of Ce silicate. In the Ce-doped silicon-rich films, the Ce emission was absent at annealing temperatures lower than 1100∘C due to the strong absorption of Si-ncs. Optimal film compositions and annealing conditions for maximizing the PL intensities of the rare earths in the films have been determined. The light emissions from these films were very bright and can be easily observed even under room lighting conditions.

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Synthesis of 3-dimensional porous graphene nanosheets using electron cyclotron resonance plasma enhanced chemical vapour deposition

RSC Advances ◽

10.1039/c5ra09087c ◽

2015 ◽

Vol 5 (103) ◽

pp. 84927-84935 ◽

Cited By ~ 10

Author(s):

Rajesh Thomas ◽

G. Mohan Rao

Keyword(s):

Chemical Vapour Deposition ◽

Vapour Deposition ◽

Electron Cyclotron Resonance ◽

Microwave Plasma ◽

Graphene Nanosheets ◽

Chemical Vapour ◽

Hydrogen Gas ◽

3 Dimensional ◽

Gas Molecules ◽

Resonance Plasma

Microwave plasma driven chemical vapour deposition was used to synthesize graphene nanosheets from a mixture of acetylene and hydrogen gas molecules.

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(Invited) Study of Rare Earth Doped Silicon-Based Dielectric Films Using Synchrotron Radiation

ECS Meeting Abstracts ◽

10.1149/ma2011-01/19/1246 ◽

2011 ◽

Keyword(s):

Rare Earth ◽

Synchrotron Radiation ◽

Dielectric Films ◽

Doped Silicon ◽

Silicon Based ◽

Rare Earth Doped

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Light Emission from Intrinsic and Doped Silicon-Rich Silicon Oxide: from the Visible to 1.6 ΜM

MRS Proceedings ◽

10.1557/proc-452-523 ◽

1996 ◽

Vol 452 ◽

Cited By ~ 2

Author(s):

L. Tsybeskov ◽

K. L. Moore ◽

P. M. Fauchet ◽

D. G. Hall

Keyword(s):

Rare Earth ◽

External Quantum Efficiency ◽

Room Temperature ◽

Structural Modification ◽

Silicon Oxide ◽

Light Emission ◽

Crystalline Silicon ◽

Light Emitting ◽

Infra Red ◽

Doped Silicon

AbstractSilicon-rich silicon oxide (SRSO) films were prepared by thermal oxidation (700°C-950°C) of electrochemically etched crystalline silicon (c-Si). The annealing-oxidation conditions are responsible for the chemical and structural modification of SRSO as well as for the intrinsic light-emission in the visible and near infra-red spectral regions (2.0–1.8 eV, 1.6 eV and 1.1 eV). The extrinsic photoluminescence (PL) is produced by doping (via electroplating or ion implantation) with rare-earth (R-E) ions (Nd at 1.06 μm, Er at 1.5 μm) and chalcogens (S at ∼1.6 μm). The impurities can be localized within the Si grains (S), in the SiO matrix (Nd, Er) or at the Si-SiO interface (Er). The Er-related PL in SRSO was studied in detail: the maximum PL external quantum efficiency (EQE) of 0.01–0.1% was found in samples annealed at 900°C in diluted oxygen (∼ 10% in N2). The integrated PL temperature dependence is weak from 12K to 300K. Light emitting diodes (LEDs) with an active layer made of an intrinsic and doped SRSO are manufactured and studied: room temperature electroluminescence (EL) from the visible to 1.6 μmhas been demonstrated.

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The Nd-nanocluster Coupling Strength and its Effect in Excitation/de-excitation of Nd3+ Luminescence in Nd-doped Silicon-rich Silicon Oxide

MRS Proceedings ◽

10.1557/proc-770-i6.10 ◽

2003 ◽

Vol 770 ◽

Author(s):

Se-Young Seo ◽

Jung H. Shin

Keyword(s):

Coupling Strength ◽

Cyclotron Resonance ◽

Transfer Rate ◽

Silicon Oxide ◽

Electron Cyclotron Resonance ◽

Chemical Vapor ◽

Temperature Quenching ◽

Doped Silicon ◽

Back Transfer ◽

Resonance Plasma

AbstractThe Nd-nanocluster Si (nc-Si) coupling strength and its effect in excitation/de-excitation of Nd3+ luminescence in Nd-doped silicon-rich silicon oxide (SRSO) is investigated. Nd-doped SRSO thin films, which consist of nc-Si embedded inside a SiO2 matrix, were prepared by electron-cyclotron-resonance plasma enhanced chemical vapor deposition (ECR-PECVD) of SiH4 and O2 with co-sputtering of Nd and subsequent anneal at 950 °C. Efficient Nd3+ luminescence with moderate temperature quenching is observed. Based on the temperature dependence of Nd3+ luminescence lifetime, a coupling strength between nc-Si and Nd that is strong enough to result in efficient excitation of Nd3+ via quantum confined excitons while weak enough to result in a small back-transfer rate is identified as the key to Nd3+ luminescence.

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Structure and Luminescence of Rare Earth-Doped Silicon Oxides Studied Through XANES and XEOL

ECS Meeting Abstracts ◽

10.1149/ma2009-02/44/3228 ◽

2009 ◽

Keyword(s):

Rare Earth ◽

Silicon Oxides ◽

Doped Silicon ◽

Rare Earth Doped

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Self assembled gold and silver nanoparticulates on silicon nanotips as surface enhanced Raman active substrates

MRS Proceedings ◽

10.1557/proc-788-l2.5 ◽

2003 ◽

Vol 788 ◽

Author(s):

S. Chattopadhyay ◽

H. C. Lo ◽

K. H. Chen ◽

C. H. Hsu ◽

L. C. Chen

Keyword(s):

Vapour Deposition ◽

Electron Cyclotron Resonance ◽

Ion Beam ◽

Chemical Vapour ◽

Surface Enhanced Raman Spectroscopy ◽

Plasma Chemical ◽

Surface Enhanced ◽

Surface Enhanced Raman ◽

Plasma Chemical Vapour Deposition ◽

Resonance Plasma

AbstractSilicon nanotips, grown via electron cyclotron resonance plasma chemical vapour deposition, with apex diameters of ∼2nm and lengths of 1000 nm and densities of 1011/cm2 were used as a new substrate for surface enhanced Raman spectroscopy. Ion beam sputtered gold and silver self assemble on these substrates as nanoparticulates of 4–10 nm diameter and these metallic nanoparticulates assist in the surface enhancement of Raman signals of analytes. Molecules such as Rhodamine 6G and bis-Pyridyl ethylene of varied concentrations, in the range of 10-6-10-10 M, has been studied on these substrates and enhancements in the range of 106-108 were observed.

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