TY - JOUR
T1 - Pseudorotational epitaxy of self-assembled octadecyltrichlorosilane monolayers on sapphire (0001)
AU - Steinrück, H. G.
AU - Magerl, A.
AU - Deutsch, M.
AU - Ocko, B. M.
N1 - Publisher Copyright:
© 2014 American Physical Society.
PY - 2014/10/10
Y1 - 2014/10/10
N2 - The structure of octadecyltrichlorosilane self-assembled monolayers (SAMs) on sapphire (0001) was studied by Å-resolution surface-specific x-ray scattering methods. The monolayer was found to consist of three sublayers where the outermost layer corresponds to vertically oriented, closely packed alkyl tails. Laterally, the monolayer is hexagonally packed and exhibits pseudorotational epitaxy to the sapphire, manifested by a broad scattering peak at zero relative azimuthal rotation, with long powderlike tails. The lattice mismatch of ∼1%-3% to the sapphire's and the different length scale introduced by the lateral Si-O-Si bonding prohibit positional epitaxy. However, the substrate induces an intriguing increase in the crystalline coherence length of the SAM's powderlike crystallites when rotationally aligned with the sapphire's lattice. The increase correlates well with the rotational dependence of the separation of corresponding substrate-monolayer lattice sites.
AB - The structure of octadecyltrichlorosilane self-assembled monolayers (SAMs) on sapphire (0001) was studied by Å-resolution surface-specific x-ray scattering methods. The monolayer was found to consist of three sublayers where the outermost layer corresponds to vertically oriented, closely packed alkyl tails. Laterally, the monolayer is hexagonally packed and exhibits pseudorotational epitaxy to the sapphire, manifested by a broad scattering peak at zero relative azimuthal rotation, with long powderlike tails. The lattice mismatch of ∼1%-3% to the sapphire's and the different length scale introduced by the lateral Si-O-Si bonding prohibit positional epitaxy. However, the substrate induces an intriguing increase in the crystalline coherence length of the SAM's powderlike crystallites when rotationally aligned with the sapphire's lattice. The increase correlates well with the rotational dependence of the separation of corresponding substrate-monolayer lattice sites.
UR - http://www.scopus.com/inward/record.url?scp=84907855049&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.113.156101
DO - 10.1103/PhysRevLett.113.156101
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C2 - 25375723
AN - SCOPUS:84907855049
SN - 0031-9007
VL - 113
JO - Physical Review Letters
JF - Physical Review Letters
IS - 15
M1 - 156101
ER -