Multifractal and optical bandgap characterization of Ta2O5 thin films deposited by electron gun method

• Published in: Optical and quantum electronics Vol. 52; no. 2
• Main Authors: Shakoury, Reza, Rezaee, Sahar, Mwema, Fredrick, Luna, Carlos, Ghosh, Koushik, Jurečka, Stanislav, Ţălu, Ştefan, Arman, Ali, Grayeli Korpi, Alireza
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.02.2020; Springer Nature B.V
• Subjects: Atomic force microscopy; Characterization and Evaluation of Materials; Computer Communication Networks; Electrical Engineering; Electron guns; Film thickness; Glass substrates; Lasers; Microtexture; Optical Devices; Optics; Photonics; Physics; Physics and Astronomy; Refractivity; Spectroellipsometry; Spectrophotometry; Tantalum; Tantalum oxides; Thin films; Atomic force microscopy; Optical properties; Electron gun method; Multifractal analysis; Ta; O; thin films
• ISSN: 0306-8919; 1572-817X
• DOI: 10.1007/s11082-019-2173-5

The micromorphology of tantalum pentoxide (Ta 2 O 5 ) thin films, deposited on glass substrates by electron gun method, has been analyzed using atomic force microscopy (AFM), UV–Vis–NIR spectrophotometry and multifractal analyses. Two samples were grown at basic pressure of 7 × 10 −6 mbar, work pressures of 1.3 × 10 −4 and 2.0 × 10 −4 mbar, and thicknesses of 0.38 μm and 0.39 μm, respectively. Subsequently, these samples were annealed at 300 °C for 2 h. The physical, structural and optical analyses were investigated by spectroscopic ellipsometry, spectrophotometry and AFM. The measured transmittance spectra were studied based on the Swanepoel method, whose results also yielded to the estimation of the film thickness and the refractive index. Finally, Ta 2 O 5 thin films were characterized by AFM measurements and multifractal analyses for an accurate description of the 3-D surface microtexture features. The fractal examinations of the samples revealed that these microstructures exhibit multifractal characteristics. Essential parameters that characterized the thin films were compared and discussed thoroughly.