Open Access Nano Express

Morphological, compositional, structural, and optical properties of Si-nc embedded in SiO x films

J Alberto Luna López1*, J Carrillo López1, D E Vázquez Valerdi1, G García Salgado1, T Díaz-Becerril1, A Ponce Pedraza2 and F J Flores Gracia1

Author affiliations

1 IC-CIDS Benemérita Universidad Autónoma de Puebla, Ed. 103 C o D, Col. San Manuel, C.P, Puebla, Pue, 72570, Mexico

2 Department of Physics & Astronomy, University of Texas at San Antonio, San Antonio, TX, 78249, USA

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Citation and License

Nanoscale Research Letters 2012, 7:604  doi:10.1186/1556-276X-7-604

Published: 30 October 2012

Abstract

Structural, compositional, morphological, and optical properties of silicon nanocrystal (Si-nc) embedded in a matrix of non-stoichiometric silicon oxide (SiOx) films were studied. SiOx films were prepared by hot filament chemical vapor deposition technique in the 900 to 1,400°C range. Different microscopic and spectroscopic characterization techniques were used. The film composition changes with the growth temperature as Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy reveal. High-resolution transmission electron microscopy supports the existence of Si-ncs with a diameter from 1 to 6.5 nm in the matrix of SiOx films. The films emit in a wide photoluminescent spectrum, and the maximum peak emission shows a blueshift as the growth temperature decreases. On the other hand, transmittance spectra showed a wavelength shift of the absorption border, indicating an increase in the energy optical bandgap, when the growth temperature decreases. A relationship between composition, Si-nc size, energy bandgap, PL, and surface morphology was obtained. According to these results, we have analyzed the dependence of PL on the composition, structure, and morphology of the Si-ncs embedded in a matrix of non-stoichiometric SiOx films.

Keywords:
Silicon nanocrystals; High-resolution TEM; XRD; PL; AFM; HFCVD; 61.05.-a; 68.37.Og; 61.05.cp; 78.55.-m; 68.37.Ps; 81.15.Gh