Applied Surface Science, Vol.265, 180-186, 2013
Optical and structural characterization of pulsed laser deposited ruby thin films for temperature sensing application
The ruby thin films were deposited by pulsed laser deposition (PLD) technique in an atmosphere of oxygen using ruby pellet, indigenously prepared by mixing Al2O3 and Cr2O3 in appropriate proportion. The characteristics R-1 and R-2 lines at 694.2 nm and 692.7 nm in the photoluminescence spectra of target pellet as well as that of PLD thin films, confirmed the ruby phase in both. The XRD and Raman spectra confirmed deposition of c-axis oriented crystalline ruby thin film on sapphire substrate. Effect of deposition time, substrate and deposition temperature on PLD grown thin films of ruby are reported. The intensity of R-1 and R-2 lines of PLD ruby thin films increased enormously after annealing the film at 1000 degrees C for 2 h. The film deposited on sapphire substrate for 2 h was 260 nm thick and the corresponding deposition rate was 2.16 nm/min. This film was subjected to temperature dependent photoluminescence studies. The peak positions of R-1 and R-2 lines and corresponding line width of PLD ruby thin film were observed to be blue shifted with decrease in temperature. R-1 line position sensitivity, d (v) over bar /dT, cm(-1)/K in the range 138-368 K was very well fitted to linear fit and hence can be used as temperature sensor in this range. (C) 2012 Elsevier B.V. All rights reserved.