Structural and optical characteristics of gallium oxide thin films deposited by ultrasonic spray pyrolysis

• Published in: Journal of the Electrochemical Society Vol. 148; no. 2; pp. F26 - F29
• Main Authors: ORTIZ, A, ALONSO, J. C, ANDRADE, E, URBIOLA, C
• Format: Journal Article
• Language: English
• Published: Pennington, NJ Electrochemical Society 2001
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Spray coating techniques; Amorphous material; Crystalline phase; Infrared spectroscopy; Metals Compounds; Chemical spray deposition; Refractive index; Dielectric properties; Ultrasonic treatment; Gallium oxides; Rutherford backscattering; Optical properties; Permittivity; Crystal structure
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1.1342183

Amorphous gallium oxide thin films were prepared by ultrasonic spray pyrolysis using gallium acetylacetonate as source material and water as oxidiser. Samples annealed at 850 C during 1 h show the crystalline beta-phase of Ga2O3. Rutherford backscattering results indicate that both as-deposited and annealed films have the stoichiometric chemical composition without incorporation of carbon impurities. IR spectroscopic measurements show that there is no incorporation of O-H and Ga-OH radicals in any of the studied films. The IR spectra for amorphous films show a broad absorption band from 400 to 900 cm-1, typical for some amorphous metallic oxides. Meanwhile, for the annealed films the IR spectra show well-defined peaks located at 450 and 670 cm-1 related to the beta-phase of Ga2O3. The refractive index of the films shows a strong change from 1.846 for the amorphous films to 1.935 for the annealed ones. The optical bandgap energy values are 4.94 eV for the as-deposited films and 4.99 eV for the annealed films. All these changes are associated with a different microstructure of the annealed films. 31 refs.