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Chromium nanostructures formed by dewetting of heteroepitaxial films on W(100)

DOI: 10.1103/PhysRevB.86.045454 DOI Help

Authors: Roger Bennett (University of Reading) , James Mulley (University of Reading) , Haitham Etman (University of Reading) , Ailsa Sparkes (University of Reading) , Tugce Eralp (University of Reading) , Georg Held (University of Reading) , Stuart Cavill (Diamond Light Source) , Sarnjeet Dhesi (Diamond Light Source)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review B , VOL 86 (4)

State: Published (Approved)
Published: July 2012
Diamond Proposal Number(s): 75

Abstract: In this paper, we report the surprising formation of square-based facetted islands with linear dimension of the order of 500 nm upon dewetting of a Cr multilayer on W(100). We show that these square islands are composed of inclined facets surrounding a depressed center such that the facet slopes inward with the outer edges of the islands thicker than the centers. The islands’ shapes do not represent traditional equilibrium crystal shapes as expected for a Wulf construction. In situ UV and x-ray photoelectron emission microscopy allied to spatially resolved spectroscopy throws considerable light on the nature of the dewetting and shows that the metal surface between the islands remains covered by a thin pseudomorphic wetting layer of ∼1 ML. Low-energy electron diffraction and scanning tunneling and atomic force microscopies allow quantification of facet slopes, and we identify a predominance of tilted Cr(100) facets ±5° off of the substrate normal bound by (210) planes at ∼26°. The epitaxial Cr islands adopt the bulk Cr lattice constant but are tilted with respect to the surface normal. We suggest that the Cr crystallite tilting creates a vicinal-like interface structure that determines the island morphology.

Subject Areas: Physics, Materials, Chemistry

Instruments: I06-Nanoscience