Oxidation and phase transitions of epitaxial tin oxide thin films on ({bar 1}012) sapphire

Journal Article · Fri Jun 01 04:00:00 EDT 2001 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1368865· OSTI ID:40203717

Pan, X Q; Fu, L

We studied the structural behavior and electrical transport properties of epitaxial {alpha}-SnO thin films grown on the ({bar 1}012){alpha}-Al{sub 2}O{sub 3} (sapphire) substrate. Hall effect measurements revealed that the epitaxial as-deposited SnO film is a p-type semiconductor. In situ x-ray diffraction studies show that the {alpha}-SnO phase is metastable and will transform into SnO{sub 2} with the rutile type structure when annealed at high temperatures in air. The onset of this phase transformation was observed to begin approximately at 300{degree}C during heating. Shortly thereafter, rutile SnO{sub 2} was observed to coexist with {alpha}-SnO and intermediate products such as Sn and Sn{sub 3}O{sub 4}. After being annealed at temperatures above 600{degree}C, the film then fully transformed into the rutile SnO{sub 2} phase. Our results show that the {alpha}-SnO to SnO{sub 2} structural transformation proceeds initially by the localized disproportionate redistribution of internal oxygen at low temperature, followed by the transformation of the remaining SnO phase and intermediate phases into SnO{sub 2} via the inward diffusion of external oxygen at higher temperatures. Most of the SnO{sub 2} crystallites nucleate epitaxially on {alpha}-SnO with the orientation relationship of (101){sub SnO{sub 2}}//(001){sub SnO} and their growth processes are controlled by the (101){sub SnO{sub 2}}//(001){sub SnO} interfaces, leading to a (101) texture and a laminar grain shape for SnO{sub 2}. The relationship between the electrical transport properties and the structural evolution of the film has also been investigated. {copyright} 2001 American Institute of Physics.

• Sponsoring Organization: (US)
• OSTI ID: 40203717
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 89; ISSN 0021-8979
• Publisher: The American Physical Society
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
HALL EFFECT
OXIDATION
PHASE TRANSFORMATIONS
RUTILE
SAPPHIRE
THIN FILMS
TIN OXIDES
TRANSFORMATIONS
X-RAY DIFFRACTION