Spray pyrolytic deposition of transparent aluminum oxide (Al2O3) films

• Published in: Applied surface science Vol. 258; no. 3; pp. 1091 - 1096
• Main Authors: Dhonge, Baban P., Mathews, Tom, Sundari, S. Tripura, Thinaharan, C., Kamruddin, M., Dash, S., Tyagi, A.K.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.11.2011; Elsevier
• Subjects: Aluminum oxide; Bonding; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition; Ethyl alcohol; Exact sciences and technology; Particle size; Physics; Refractive index and band gap; Spray pyrolysis; Sprayers; Sprays; Transparent Al2O3 thin films; X-ray photoelectron spectroscopy; Transparent Al2O3 thin films; Spray pyrolysis; Refractive index and band gap; Aluminium oxide; Pyrolysis; Energy gap; Transparent thin film; Inorganic compounds; Refractive index; Aluminium
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2011.09.040

► Transparent thin films of alumina were synthesized by ultrasonic spray pyrolysis. ► The refractive index, film thickness and band gap were measured by ellipsometry and UV–vis spectroscopy. ► The compositional analysis and chemical bonding in the films were done using X-ray photoelectron and FTIR spectroscopy. Optically transparent Al2O3 films has been synthesized, on quartz substrates at 500, 600 and 700°C, from 0.02M aluminum acetyl acetonate (Al(acac)3) in ethanol, by using ultrasonic spray pyrolysis technique. The films synthesized at 500, 600 and 700°C are amorphous having average particle sizes 27±6, 18±3 and 14±3, respectively. The films are found to be 95% optically transparent in the visible region. The optical transparency of the films in the ultraviolet region is found to increase with increase in deposition temperature. The observed increase in optical band gap and decrease in refractive index is attributed to the decrease in particle size with increase in deposition temperature. The stoichiometry and chemical bonding of the amorphous film studied using XPS and FTIR spectroscopy revealed the presence chemisorbed oxygen.