Suppression of near-edge optical absorption band in sputter deposited HfO{sub 2}-Al{sub 2}O{sub 3} nanolaminates containing nonmonoclinic HfO{sub 2}

Journal Article · Mon Apr 07 00:00:00 EDT 2008 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.2907331· OSTI ID:21101979

Hoppe, E E; Aita, C R ^[1]

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1. Advanced Coatings Experimental Laboratory, University of Wisconsin-Milwaukee, P.O. Box 784, Milwaukee, Wisconsin 53201 (United States)

Nanolaminates of polycrystalline (tetragonal+orthorhombic) HfO{sub 2} and amorphous Al{sub 2}O{sub 3} are sputter deposited on unheated fused SiO{sub 2}, air annealed at 573-1273 K, and analyzed by x-ray diffraction and spectrophometry. Significant O 2p{yields}Hf 5d interband absorption occurs in all films at energy E{>=}6.2 eV. For E<6.2 eV, films annealed below 1273 K retain a featureless optical absorption edge despite further crystallization. A band with a 5.65 eV onset concurrently develops with m-HfO{sub 2} crystallization after a 1273 K anneal, indicating this phase and not nanocrystallinity per se is responsible for increased absorption.

• OSTI ID: 21101979
• Journal Information: Applied Physics Letters, Vol. 92, Issue 14; Other Information: DOI: 10.1063/1.2907331; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION
ALUMINIUM OXIDES
ANNEALING
CRYSTALLIZATION
DEPOSITION
HAFNIUM OXIDES
NANOSTRUCTURES
ORTHORHOMBIC LATTICES
POLYCRYSTALS
SILICON OXIDES
SPECTROPHOTOMETRY
SPUTTERING
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
THIN FILMS
X-RAY DIFFRACTION