Direct observation of the growth process of hetero-molecular interface

2014 Fiscal Year Final Research Report

• Project/Area Number: 25620070
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Functional solid state chemistry
• Research Institution: National Institute for Materials Science
• Principal Investigator: WAKAYAMA Yutaka 独立行政法人物質・材料研究機構, 国際ナノアーキテクトニクス研究拠点, MANA研究者 (00354332)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: 超格子 / 有機半導体 / ヘテロ界面 / 走査型トンネル電子顕微鏡

Outline of Final Research Achievements

The main purpose of this study is to establish a growth process of molecular superlattice, where heterogeneous molecular layers are stacked layer-by-layer in a single molecular level. First, STM observation was carried out to clarify the formation process of hetero-interface of fluorinated phthalocyanine and pentacene as a typical combination of n-type and p-type organic semiconductors. We found that these molecules formed well-mixed bilayers, e.g., molecular alloy bilayer and solid solution, which were depending on the sequence of deposition. Here, hydrogen bonding between fluorine atoms and hydrogen atoms were found to be responsible to these mixed layer growth, that is, these intermolecular interaction prevented well-defined molecular hetero-interface. Based on these findings, we adopted a perylene derivative and thiophene oligomer, which have no intermolecular interaction. As a result, we successfully formed well-defined hetero-molecular interface with flat interface.

Free Research Field

有機半導体工学