Crystalline ultrasmooth self-assembled monolayers of alkylsilanes for organic field-effect transistors

Yutaka Ito; Ajay A Virkar; Stefan Mannsfeld; Joon Hak Oh; Michael Toney; Jason Locklin; Zhenan Bao

doi:10.1021/ja9029957

Crystalline ultrasmooth self-assembled monolayers of alkylsilanes for organic field-effect transistors

J Am Chem Soc. 2009 Jul 8;131(26):9396-404. doi: 10.1021/ja9029957.

Authors

Yutaka Ito¹, Ajay A Virkar, Stefan Mannsfeld, Joon Hak Oh, Michael Toney, Jason Locklin, Zhenan Bao

Affiliation

¹ Department of Chemical Engineering, Stanford University, 381 North South Mall, Stanford, California 94305, USA. yutaka_1.ito@toppan.co.jp

PMID: 19518097
DOI: 10.1021/ja9029957

Abstract

Crystalline self-assembled monolayers (SAMs) of organosilane compounds such as octadecyltrimethoxysilane (OTMS) and octadecyltrichlorosilane (OTCS) were deposited by a simple, spin-casting technique onto Si/SiO(2) substrates. Fabrication of the OTMS SAMs and characterization using ellipsometry, contact angle, atomic force microscopy (AFM), grazing angle attenuated total reflectance Fourier transform infrared (GATR-FTIR) spectroscopy and grazing incidence X-ray diffraction (GIXD) are described. The characterization confirms that these monolayers exhibit a well-packed crystalline phase and a remarkably high degree of smoothness. Semiconductors deposited by vapor deposition onto the crystalline OTS SAM grow in a favorable two-dimensional layered growth manner which is generally preferred morphologically for high charge carrier transport. On the OTMS SAM treated dielectric, pentacene OFETs showed hole mobilities as high as 3.0 cm(2)/V x s, while electron mobilities as high as 5.3 cm(2)/V x s were demonstrated for C(60).