UV–visible reflectivity study of the synthesis and growth of nanocrystals obtained by ion implantation

The reflectivity ( R) in the UV–visible range was used to study CdS nanocrystals obtained by implantation of Cd and S ions into SiO 2 and subsequent annealing ( T a=300–900°C). We demonstrate that such an analysis can give very useful information about the process of nanocrystal formation and growth...

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Bibliographic Details
Published inVacuum Vol. 67; no. 3; pp. 451 - 455
Main Authors Desnica, U.V, Desnica-Frankovic, I.D, Gamulin, O, White, C.W, Sonder, E, Zuhr, R.A
Format Journal Article Conference Proceeding
LanguageEnglish
Published Oxford Elsevier Ltd 26.09.2002
Elsevier
Subjects
Cadmium sulfide
CdS
Cross-disciplinary physics: materials science; rheology
Exact sciences and technology
II–VI
Implantation
Materials science
Nanocrystals
Nanoscale materials and structures: fabrication and characterization
Physics
Reflectivity
Reflectivity
II–VI
Implantation
Nanocrystals
CdS
Cadmium sulfide
Ion implantation
Inorganic compounds
Transition element compounds
Cadmium sulfides
Amorphous state
Experimental study
II-VI semiconductors
Silicon oxides
Optical method
Control method
Nanocomposite
Thermal annealing
Optical reflection
Nanostructured materials
Nanocrystal
Ultraviolet visible spectrometry
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Summary:The reflectivity ( R) in the UV–visible range was used to study CdS nanocrystals obtained by implantation of Cd and S ions into SiO 2 and subsequent annealing ( T a=300–900°C). We demonstrate that such an analysis can give very useful information about the process of nanocrystal formation and growth. The synthesis of even a small fraction of CdS is readily observable through the appearance of interference fringes since the refractive index of CdS, n CdS, is substantially higher than that of SiO 2, n SiO 2 . Extensive CdS synthesis, resulting in strong fringes, occurs for T a⩾500°C. In addition, for higher T a, a peak in R with a maximum at 2.45 eV ( R 2.45) becomes discernable indicating the formation of larger nanocrystals. It is shown that the blue shift of R 2.45 relative to its energy in the bulk CdS closely corresponds to the shift of bandgap, E g, with crystallite size and may, therefore, be used to estimate the size of the nanocrystals.
ISSN:0042-207X
1879-2715
DOI:10.1016/S0042-207X(02)00230-0