Anisotropy, band-to-band transitions, phonon modes, and oxidation properties of cobalt-oxide core-shell slanted columnar thin films
2016 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 108, no 5, 051905- p.Article in journal (Refereed) PublishedText
Highly ordered and spatially coherent cobalt slanted columnar thin films (SCTFs) were deposited by glancing angle deposition onto silicon substrates, and subsequently oxidized by annealing at 475 degrees C. Scanning electron microscopy, Raman scattering, generalized ellipsometry, and density functional theory investigations reveal shape-invariant transformation of the slanted nanocolumns from metallic to transparent metal-oxide core-shell structures with properties characteristic of spinel cobalt oxide. We find passivation of Co-SCTFs yielding Co-Al2O3 core-shell structures produced by conformal deposition of a few nanometers of alumina using atomic layer deposition fully prevents cobalt oxidation in ambient and from annealing up to 475 degrees C. (C) 2016 AIP Publishing LLC.
Place, publisher, year, edition, pages
AMER INST PHYSICS , 2016. Vol. 108, no 5, 051905- p.
IdentifiersURN: urn:nbn:se:liu:diva-127582DOI: 10.1063/1.4941399ISI: 000373055700028OAI: oai:DiVA.org:liu-127582DiVA: diva2:926001
Funding Agencies|National Science Foundation (NSF) through Center for Nanohybrid Functional Materials [EPS-1004094]; Nebraska Materials Research Science and Engineering Center [DMR-1420645]; Army Research Office [W911NF-09-C-0097]; NSF [CMMI 1337856, EAR 1521428]; Nebraska Center for Energy Sciences Research [12-00-13]; Swedish Governmental Agency for Innovation Systems (VINNOVA) [2014-04712]; J.A. Woollam Foundation2016-05-032016-05-032016-05-03