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Packing structure of MPS SAMs and its influence on oriented deposition of SnO 2 crystal films
Author(s) -
Zhang Jinli,
Zhang Ming,
Li Wei,
Zhai Yi
Publication year - 2007
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.11305
Subject(s) - monolayer , zigzag , crystallography , chemistry , x ray photoelectron spectroscopy , density functional theory , crystal (programming language) , molecular dynamics , dihedral angle , crystal structure , molecule , nanotechnology , materials science , chemical engineering , computational chemistry , geometry , organic chemistry , hydrogen bond , mathematics , computer science , engineering , programming language
The (110) crystal plane of SnO 2 was found by X‐ray diffraction, atomic force microscopy and X‐ray photoelectron spectroscopy to grow preferentially in the direction of short‐chain sulfonate self‐assembled monolayer (SAM) formed from in situ oxidation of 3‐mercaptopropyltrimethoxysilane (MPS) treated Si substrates. Molecular simulations were performed to study the optimal packing structure of MPS SAMs on Si (100) surface as well as its induced deposition mechanism to the SnO 2 crystal. Molecular mechanics calculations showed that the MPS molecules self‐assembled on Si (100) surfaces with a coverage ratio of 50% and a zigzag‐like packing pattern. Molecular dynamics calculations reflected that oxidation of the SH of MPS contributed to uniform SO 3 H‐terminated SAMs with narrower distribution of dihedral angles. Density functional theory calculations suggested the existence of strong interactions between the SO 3 H groups of SAMs and SnO 2 (110) plane, which was due to the structural and electrical match between the SO 3 H group and the unsaturated atoms on SnO 2 (110) plane. These results consistently confirmed that the ordered SAMs with SO 3 H terminal group are beneficial to the epitaxial growth of crystal SnO 2 . © 2007 American Institute of Chemical Engineers AIChE J, 2007