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Thickness dependent morphology and resistivity of ultra‐thin Al films grown on Si(111) by molecular beam epitaxy
Author(s) -
Aswal D. K.,
Joshi N.,
Debnath A. K.,
Gupta S. K.,
Vuillaume D.,
Yakhmi J. V.
Publication year - 2006
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200566102
Subject(s) - electrical resistivity and conductivity , molecular beam epitaxy , coalescence (physics) , materials science , condensed matter physics , metal , morphology (biology) , thin film , variable range hopping , thermal conduction , atmospheric temperature range , epitaxy , nanotechnology , composite material , metallurgy , thermodynamics , geology , physics , paleontology , layer (electronics) , quantum mechanics , astrobiology
The morphology and electrical resistivity of ultrathin Al metal films grown on (111) Si substrates using molecular‐beam epitaxy have been investigated. For thickness <60 nm, the film morphology consists of a two‐dimensional network of Al islands, which grows via Volmer–Weber mechanism. The coalescence of islands is found to begin at a thickness of 60 nm. The room‐temperature value of resistivity, contrary to the theoretical predictions of existing models, is found to increase monotonically with thickness. Also the temperature dependence of these films exhibited a metal‐to‐insulator transition at 110 K. The anomalous temperature dependences of resistivity have been explained using a two‐dimensional variable range hopping conduction (2d‐VRH) mechanism. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)