Evaluation of the radiative recombination mechanism in Si nanocrystals embedded in silica matrix

Date

2008-02-01

Author

Righini, Marcofabio
Gnoli, Andrea
Razzari, Luca
Serincan, Ugur
Turan, Raşit

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

215
views

0
downloads

We report measurements of the temperature dependence of photoluminescence (PQ life-time and efficiency of Si nanocrystals (Si-Nc) embedded in silica matrix. We use a practical technique based on lock-in acquisition that allows us to simultaneously evaluate, at each emission-energy, intensity and decay-time of the detected signal. Samples are prepared by Silicon-ion implantation in a SiO2 layer followed by thermal annealing. The implantation dose of Si ions ranges between 2 x 10(16) cm(-2) and 2 x 10(17) cm(-2). Intensity of Si-Nc PL shows the characteristic rising by increasing the temperature up to similar to 100 K followed by a flattening or a weak reduction up to room temperature. This behaviour reveals a population of radiative states built up by a thermally activated process. Similarly, the measured PL decay-rate is not constant with temperature but shows evidence of a thermal activation. By measuring on different samples the activation energies E-a involved in the temperature dependence of PIL intensity and decay time we verify that in all these processes E-a is a decreasing function of implantation dose (i.e., of crystallite size). This result is consistent with models connecting radiative recombination to excitons confined inside Si-Nc, in seeming contrast with the common attribution of PL of non-passivated Si-Nc to the recombination from surface/interface states. To verify the consistency of this statement, we have compared our experimental data with the predictions of quantum confinement theory obtaining an excellent agreement.

Subject Keywords

General Materials Science, Bioengineering, General Chemistry, Condensed Matter Physics, Biomedical Engineering

URI

https://hdl.handle.net/11511/37555

Journal

JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY

DOI

https://doi.org/10.1166/jnn.2008.a138

Collections

Department of Physics, Article

Suggestions

OpenMETU
Core

Preparation of iron oxide nanoparticles by microwave synthesis and their characterization Acarbas, Ozge; Ozenbas, Macit (American Scientific Publishers, 2008-02-01) In this study production of fine particle Fe2O3 via microwave processing of Fe(NO3)(3)center dot nH(2)O followed by low temperature annealing was reported. XRD was used to characterize the structural properties of nanoparticles. Approximate particle sizes were between 3-13 nm according to Scherrer's equation. Single point BET measurement results also show that samples have large surface area and they are nanometer sized particles. TEM study was conducted to examine the structure of the nanoparticles. TEM fi...
Analysis of the Specific Heat in the Supercooled Solid Phase of Liquid Crystals Kilit, Emel; Yurtseven, Hasan Hamit (Informa UK Limited, 2011-01-01) The specific heat Cp is analyzed using the experimental data at various temperatures in the solid phase of cholesteryl myristate according to a power-law formula for the rapidly and slowly cooled solid in the stability limit. We also analyze the temperature dependence of the Cp using the experimental data for the supercooled solid phase of p-azoxyanisole in the stability limit and the stability temperatures are determined for both cholesteryl myristate and p-azoxyanisole.
Investigation of carrier scattering mechanisms in TIInS2 single crystals by Hall effect measurements Qasrawi, AF; Hasanlı, Nızamı (Wiley, 2004-05-01) TlInS2 single crystals are studied through the conductivity and Hall effect measurements in the temperature regions of 100-400 and 170-400 K, respectively. An anomalous behavior of Hall voltage, which changes sign below 315 K, is interpreted through the existence of deep donor impurity levels that behave as acceptor levels when are empty. The hole and electron mobility are limited by the hole- and electron-phonon short range interactions scattering above and below 315 K, respectively. An energy level of 35 ...
Determination of deep trapping center parameters in as-grown Tl2Ga2S3Se layered crystals YILDIRIM, TACETTİN; Hasanlı, Nızamı (Elsevier BV, 2009-09-01) Thermally stimulated current measurements were carried out on as-grown Tl2Ga2S3Se layered single crystals. The investigations were performed in temperatures ranging from 10 to 320 K with heating rates of 0.6-1.2 K s(-1). The analysis of the data revealed the hole trap level located at 498 meV. The activation energies of the traps have been determined using various methods of analysis, and they agree with each other. The calculation for these traps yielded 2.1 x 10(-18) cm(2) for capture cross-section and 2....
Enhancement of H-2 Storage in Carbon Nanotubes via Doping with a Boron Nitride Ring Onay, Aytun Koyuncular; Erkoç, Şakir (American Scientific Publishers, 2009-04-01) Hydrogen storage capacity of carbon nanotubes with different chirality have been investigated by performing quantum chemical methods at semiempirical and DFT levels of calculations. It has been found that boron nitrite substitutional doping increases the hydrogen storage capacity of carbon nanotubes.

Citation Formats

M. Righini, A. Gnoli, L. Razzari, U. Serincan, and R. Turan, “Evaluation of the radiative recombination mechanism in Si nanocrystals embedded in silica matrix,” JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY, pp. 823–827, 2008, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/37555.