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Cathodoluminescence of SiO x under‐stoichiometric silica layers
Author(s) -
Salh Roushdey,
von Czarnowski A.,
Zamoryanskaya M. V.,
Kolesnikova E. V.,
Fitting H.J.
Publication year - 2006
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200521443
Subject(s) - cathodoluminescence , luminescence , stoichiometry , analytical chemistry (journal) , amorphous solid , materials science , silicon , fourier transform infrared spectroscopy , mineralogy , crystallography , chemistry , chemical engineering , optoelectronics , chromatography , engineering , metallurgy
Under‐stoichiometric thin silica layers SiO x with different stoichiometric degree 1 ≤ x ≤ 2, were prepared by thermal evaporation of silicon monoxide in vacuum and in ambient oxygen atmosphere of various pressure onto crystalline silicon substrates. The chemical composition has been determined by Fourier transform infrared spectroscopy (FTIR). A special formula is derived to correlate the stoichiometric degree x with the wavenumber of the main TO stretching mode (Si–O–Si) in silica, finally to determine the actual composition values x of the layers. Cathodoluminescence (CL) of these layers shows the development of typical amorphous SiO 2 luminescence bands at the composition threshold x > 1.5 and then onwards to x = 2. These luminescence bands were observed at 4.3, 2.7, 2.15, and 1.9 eV. The green–yellow luminescence (2.15 eV) is strongly increasing with the annealing temperature up to 1300 °C and is assigned to phase separation of SiO x into Si and SiO 2 and formation of hexamer silicon rings in the understoichiometric silica network. Finally we observe Si nanoclusters by means of transmission elec‐ tron microscopy (TEM) micrographs. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)