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Formation and Growth of Semiconductor PbTe Nanocrystals in a Borosilicate Glass Matrix
Author(s) -
Craievich A. F.,
Alves O. L.,
Barbosa L. C.
Publication year - 1997
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889897001799
Subject(s) - nanocrystal , materials science , borosilicate glass , small angle x ray scattering , scattering , semiconductor , molecular physics , absorption (acoustics) , radius , analytical chemistry (journal) , condensed matter physics , nanotechnology , optics , composite material , chemistry , optoelectronics , physics , chromatography , computer security , computer science
Pb‐ and Te‐doped borosilicate glasses are transformed by appropriate heat treatment into a composite material consisting of a vitreous matrix in which semiconductor PbTe nanocrystals are embedded. This composite exhibits interesting non‐linear optical properties in the infrared region, in the range 10–20 000 Å. The shape and size distribution of the nanocrystals and the kinetics of their growth were studied by small‐angle X‐ray scattering (SAXS) during in situ isothermal treatment at 923 K. The experimental results indicate that nanocrystals are nearly spherical and have an average radius increasing from 16 to 33 Å after 2 h at 923 K, the relative size dispersion being time‐invariant and approximately equal to 8%. This investigation demonstrates that the kinetics of nanocrystal growth are governed by the classic mechanism of atomic diffusion. The radius of nanocrystals, deduced by applying the simple Efros & Efros [ Sov. Phys. Semicond. (1982), 16 , 772–775] model using the energy values corresponding to the exciton peaks of optical absorption spectra, does not agree with the average radius determined by SAXS.