Investigations of the crystallization mechanism of CrSb and CrSb{sub 2} multilayered films using in-situ X-ray diffraction and in-situ X-ray reflectometry
- Institute of Inorganic Chemistry, Christian-Albrechts-University of Kiel, Max-Eyth-Str. 2, 24118 Kiel (Germany)
- Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstr. 5-13, D-81377 Muenchen (Germany)
Chromium and antimony multilayered films with variable elemental layer thickness were deposited on (1 0 0)-Si substrate cooled with liquid nitrogen. The stoichiometry of the films was adjusted to Cr:Sb=1:1 and 1:2. The thickness of Cr-Sb repeating units of these multifilms was varied between 11.4 and 102.5 A. Satellite maxima in the X-ray reflectivity curves observed for films in the as-deposited state demonstrate an alternating stacking of the evaporated elements. The reactivity of the superlattice reactants was investigated with temperature dependent in-situ X-ray diffractometry and X-ray reflectometry. The crystallization temperature of CrSb depends on the double-layer thickness and is about 90 Degree-Sign C for a Cr:Sb ratio of 1:1 and double-layer thickness of 53.7 A where nucleation and crystal formation occurs at the element interfaces, while for a thin double-layer thickness (11.4 A) first interdiffusion of the elements occurs before crystallization starts, i.e., an amorphous intermediate is formed prior to crystallization of CrSb. A decomposition reaction into CrSb{sub 2} occurs at about 230 Degree-Sign C, and up to about 575 Degree-Sign C, CrSb, CrSb{sub 2} and amorphous Cr coexist. For the ratio Cr:Sb=1:2 and a thin double-layer thickness prior to crystallization of CrSb{sub 2} nano-sized crystallites with a composition near CrSb{sub 2} nucleate and grow. These crystallites are then successively transformed in long-range ordered crystals exhibiting a pronounced preferred orientation. For films with a thicker repeat unit first formation of CrSb is observed which then reacts with elemental Sb yielding crystalline CrSb{sub 2}. An activation energy for interdiffusion of Cr and Sb of about 1.8 eV is estimated for a film with Cr:Sb=1:1 exhibiting a double-layer thickness of about 53.7 A and an energy for crystal growth of about 1.1 eV. For the film with the thinner double-layer thickness of 11.4 A a lower value of the activation energy for interdiffusion is obtained. For CrSb{sub 2} the energy for crystal growth is about 3.0 eV being significantly larger than for CrSb. Specific resistivity and Hall coefficient measurements were performed for crystalline CrSb and CrSb{sub 2} films. The temperature-dependent resistivity measurement exhibits a metallic behavior for CrSb and semi-conducting properties for CrSb{sub 2}. - Graphical abstract: The compound CrSb{sub 2} crystallizes from the amorphous state via intermediate formation of CrSb. Highlights: Black-Right-Pointing-Pointer CrSb and CrSb{sub 2} crystallize at very low temperatures in multilayered films. Black-Right-Pointing-Pointer Film thickness determines crystallization at interfaces or from amorphous intermediate. Black-Right-Pointing-Pointer Prior to crystallization of CrSb{sub 2}, highly textured CrSb crystallizes first. Black-Right-Pointing-Pointer Depending on the film thickness CrSb{sub 2} exhibits different preferred orientations.
- OSTI ID:
- 22149917
- Journal Information:
- Journal of Solid State Chemistry, Vol. 196; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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