Microstructural, optical and spectroscopic studies of laser ablated nanostructured tantalum oxide thin films

Thin films of tantalum oxide (Ta 2O 5) have been prepared by pulsed laser deposition technique at different substrate temperatures (300–973 K) under vacuum and under oxygen background (pO 2 = 2 × 10 −3 mbar) conditions. The films are annealed at a temperature of 1173 K. The as-deposited films are am...

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Bibliographic Details
Published in:Applied surface science 2009-05, Vol.255 (16), p.7126-7135
Main Authors: Krishnan, Renju R., Gopchandran, K.G., MahadevanPillai, V.P., Ganesan, V., Sathe, Vasant
Format: Article
Language:English
Subjects:
Atomic force microscopy
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Condensed matter: structure, mechanical and thermal properties
Cross-disciplinary physics: materials science
rheology
Exact sciences and technology
FTIR studies
Nanostructures
Physics
Pulsed laser ablation
Raman spectra
Tantalum oxide thin films
UV–visible spectra
X-ray diffraction
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Summary:Thin films of tantalum oxide (Ta 2O 5) have been prepared by pulsed laser deposition technique at different substrate temperatures (300–973 K) under vacuum and under oxygen background (pO 2 = 2 × 10 −3 mbar) conditions. The films are annealed at a temperature of 1173 K. The as-deposited films are amorphous irrespective of the substrate temperature. XRD patterns show that on annealing, the films get crystallized in orthorhombic phase of tantalum pentoxide (β-Ta 2O 5). The annealed films deposited at substrate temperatures 300 K and 673 K have a preferred orientation along (0 0 1) plane, whereas the films deposited at substrate temperatures above 673 K show a preferred orientation along (2 0 0) crystal plane. The deposited films are characterized using techniques such as grazing incidence X-ray diffraction (GIXRD), atomic force microscopy (AFM), micro-Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy and UV–visible spectroscopy. FTIR and micro-Raman measurements confirm the presence of Ta–O, Ta–O–Ta and O–Ta–O bands in the films. Grain size calculations from X-ray diffraction and AFM show a decrease with increase in substrate temperature. The variation of transmittance and band gap with film growth parameters are also discussed.
ISSN:0169-4332
1873-5584
DOI:10.1016/j.apsusc.2009.03.059