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The Role of OTS Density on Pentacene and C 60 Nucleation, Thin Film Growth, and Transistor Performance
Author(s) -
Virkar Ajay,
Mannsfeld Stefan,
Oh Joon Hak,
Toney Michael F.,
Tan Yih Horng,
Liu Gangyu,
Scott J. Campbell,
Miller Robert,
Bao Zhenan
Publication year - 2009
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200801727
Subject(s) - pentacene , materials science , thin film transistor , organic semiconductor , nucleation , semiconductor , optoelectronics , monolayer , transistor , dielectric , surface roughness , thin film , surface energy , layer (electronics) , nanotechnology , composite material , organic chemistry , voltage , electrical engineering , chemistry , engineering
In organic thin film transistors (OTFTs), charge transport occurs in the first few monolayers of the semiconductor near the semiconductor/dielectric interface. Previous work has investigated the roles of dielectric surface energy, roughness, and chemical functionality on performance. However, large discrepancies in performance, even with apparently identical surface treatments, indicate that additional surface parameters must be identified and controlled in order to optimize OTFTs. Here, a crystalline, dense octadecylsilane (OTS) surface modification layer is found that promotes two‐dimensional semiconductor growth. Higher mobility is consistently achieved for films deposited on crystalline OTS compared to on disordered OTS, with mobilities as high as 5.3 and 2.3 cm 2 V −1 s −1 for C 60 and pentacene, respectively. This is a significant step toward morphological control of organic semiconductors which is directly linked to their thin film charge carrier transport.