Optical index profile of nonuniform depth-distributed silicon nanocrystals within SiO2

Optical properties of silicon nanocrystals (Si-ncs) prepared by silicon implantation into silicon oxide have been investigated by photoluminescence measurements and spectroscopic ellipsometry. The dielectric function associated with Si-nc uniformly and nonuniformly depth distributed has been determined by means of the Tauc–Lorentz (TL) model, using the Bruggemann effective medium approximation. The evolution of the Si-nc sublayer dielectric response as a function of the ion fluence has been established for volume fractions of Si excess varying between 9.1% and 50.4%. Comparison between the depth profile of optical indices determined by ellipsometry and TRIM calculations shows that for implanted Si volume fraction lower than 30%, the center and the width of the optical index profile agree with the spatial distribution of the implanted Si when both the swelling and the ion sputtering effects are taken into account. This is also valid in systems having two separate Si-nc sublayers, where the geometric charac...

[1]  Influence of nanocrystal size on optical properties of Si nanocrystals embedded in SiO2 synthesized by Si ion implantation , 2007 .

[2]  G G Ross,et al.  The effect of implantation dose on the microstructure of silicon nanocrystals in SiO2 , 2004 .

[3]  R. Rizk,et al.  Structural, ellipsometry and photoluminescence spectroscopy studies of silicon nanograins embedded in a silica matrix , 2001 .

[4]  Joshua M. Pearce,et al.  Analytical model for the optical functions of amorphous semiconductors from the near-infrared to ultraviolet: Applications in thin film photovoltaics , 2002, Journal of Applied Physics.

[5]  D. Marquardt.  An Algorithm for Least-Squares Estimation of Nonlinear Parameters , 1963 .

[6]  G. Jellison,et al.  Parameterization of the optical functions of amorphous materials in the interband region , 1996 .

[7]  M. Al-Kuhaili,et al.  Characterization of thin films of a-SiOx (1.1 , 2003 .

[8]  J. Biersack,et al.  A Monte Carlo computer program for the transport of energetic ions in amorphous targets , 1980 .

[9]  Effect of implanted Si concentration on the Si nanocrystal size and emitted PL spectrum , 2007 .

[10]  Friesner,et al.  Exciton spectra of semiconductor clusters. , 1991, Physical review letters.

[11]  G. Ross,et al.  Effects of oxide layer thickness on Si-nanocrystal photoluminescence intensity in Si+-implanted SiO2/Si systems , 2006 .

[12]  A. Nassiopoulou,et al.  Quantum confinement and interface structure of Si nanocrystals of sizes 3–5 nm embedded in a-SiO2 , 2007 .

[13]  F. Priolo,et al.  Formation and evolution of luminescent Si nanoclusters produced by thermal annealing of SiOx films , 2004 .

[14]  Tupei Chen,et al.  Optical properties of silicon nanocrystals embedded in a SiO2 matrix , 2005 .

[15]  Friedrich Huisken,et al.  Ellipsometric study of silicon nanocrystal optical constants , 2003 .

[16]  P. Alnot,et al.  Forouhi-Bloomer and Tauc-Lorentz optical dispersions applied using spectroscopic ellipsometry to plasma-deposited fluorocarbon films , 2007 .

[17]  François Martin,et al.  Modulation of the photoluminescence spectrum by depth selective excitation of an embedded Si-nc layer , 2004 .

[18]  G. Ross,et al.  Si implantation in SiO2: Stucture of Si nanocrystals and composition of SiO2 layer , 2007 .

[19]  D. A. G. Bruggeman.  Berechnung verschiedener physikalischer Konstanten von heterogenen Substanzen. I. Dielektrizitätskonstanten und Leitfähigkeiten der Mischkörper aus isotropen Substanzen , 1935 .

[20]  Evidence of localized amorphous silicon clustering from Raman depth-probing of silicon nanocrystals in fused silica. , 2008, Nanotechnology.

[21]  Dielectric function of nanocrystalline silicon with few nanometers (<3 nm) grain size , 2003 .

[22]  J. Grob,et al.  Correlation between silicon nanocrystalline size effect and spectroscopic ellipsometry responses , 2004 .

[23]  I. Stenger,et al.  Optical properties of Si nanocrystals embedded in SiO2 , 2005 .

[24]  B. Cheng,et al.  Origin and evolution of photoluminescence from Si nanocrystals embedded in a SiO2 matrix , 2005 .

[25]  P. Pellegrino,et al.  Size dependence of refractive index of Si nanoclusters embedded in SiO2 , 2005 .

[26]  Lin-wang Wang,et al.  Theory of silicon nanostructures , 1996 .

[27]  S. Ossicini,et al.  Ab initio study on oxidized silicon clusters and silicon nanocrystals embedded in Si O 2 : Beyond the quantum confinement effect , 2005 .