| Abstract
| - Microstructures composed of two types of organosilane self-assembled monolayers (SAMs) terminatedwith different functional groups have been constructed on silicon substrates covered with native oxide.Surface potential images of these microstructures were acquired by Kelvin-probe force microscopy (KFM).By chemical vapor deposition (CVD), the SAMs were fabricated from n-octadecyltrimethoxysilane (ODS)[H3C(CH2)17Si(OCH3)3], fluoroalkylsilane (FAS), that is, heptadecafluoro-1,1,2,2-tetrahydro-decyl-1-trimethoxysilane [F3C(CF2)7(CH2)2Si(OCH3)3], and n-(6-aminohexyl)aminopropyltrimethoxysilane (AHAPS)[H2N(CH2)6NH(CH2)3Si(OCH3)3]. Through a photolithographic technique, binary microstructures consistingof ODS/FAS and ODS/AHAPS were constructed. A surface potential contrast of the two SAMs in each ofthe binary microstructures was clearly detected by KFM. The surface potential of the FAS-terminatedregion was ca. 180 mV lower than that of the ODS-terminated region, while the potential of the AHAPS-terminated region was ca. 50 mV higher. These results agree with surface potentials of the SAMs predictedfrom dipole moments of the corresponding precursor organosilane molecules as estimated by ab initiomolecular orbital (MO) calculations. Moreover, by applying the surface potential contrasts experimentallyacquired by KFM to surface potential contrast occupied area with single molecule curves theoreticallyderived by MO calculations, packing densities of the SAMs prepared by CVD were confirmed to be smallerthan those of Langmuir−Blodgett monolayers.
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