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Optical Properties of Er‐Doped Al 2 O 3 –SiO 2 Films Prepared by a Modified Sol–Gel Process
Author(s) -
Seok Sang Il,
Lim Mi Ae,
Ju JungJin,
Lee MyungHyun
Publication year - 2005
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2005.00454.x
Subject(s) - materials science , annealing (glass) , analytical chemistry (journal) , thin film , sol gel , photoluminescence , spin coating , luminescence , doping , ellipsometry , wafer , ion , nanotechnology , composite material , chemistry , optoelectronics , organic chemistry , chromatography
Er‐doped Al 2 O 3 –SiO 2 (1/9 in mol ratio of Al 2 O 3 /SiO 2 ) thin films were prepared by using a modified sol–gel process. The modified process entails the precipitation and digestion of Er(OH) 3 , obtained from the reaction between Er ions and NH 4 OH in solution. Thin films were deposited on Si wafers by using a spin coating technique (3000 rpm) and the coated films were heat treated at different temperatures for 1 h in an oxygen‐purged furnace. All the films were structurally characterized by the X‐ray diffraction technique using Cu K α radiation. Refractive indices and the morphologies of the films were studied using a spectroscopic phase modulated ellipsometer and atomic force microscopy, respectively. It was observed that the films were crack free and of about 0.4 μm thickness in a single spin coating and both the lifetime and the photoluminescence intensity of Er ions increased with increasing the annealing temperature. The luminescence properties of the Er‐doped Al 2 O 3 –SiO 2 made by a conventional and our modified doping process were compared and discussed from the stand point of peak intensities and lifetimes as a function of annealing temperatures. It is to be noted here that our modified process was found to be more effective in reducing the clustering of Er ions in Al 2 O 3 –SiO 2 materials as compared to that of the conventional method.