ACS Appl Mater Interfaces. 2015 Jan 28;7(3):1833-40. doi: 10.1021/am507528e. Epub 2015 Jan 15.

Flat-lying semiconductor-insulator interfacial layer in DNTT thin films.

ACS applied materials & interfaces

Min-Cherl Jung, Matthew R Leyden, Gueorgui O Nikiforov, Michael V Lee, Han-Koo Lee, Tae Joo Shin, Kazuo Takimiya, Yabing Qi

PMID: 25545199 DOI: 10.1021/am507528e

Abstract

The molecular order of organic semiconductors at the gate dielectric is the most critical factor determining carrier mobility in thin film transistors since the conducting channel forms at the dielectric interface. Despite its fundamental importance, this semiconductor-insulator interface is not well understood, primarily because it is buried within the device. We fabricated dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) thin film transistors by thermal evaporation in vacuum onto substrates held at different temperatures and systematically correlated the extracted charge mobility to the crystal grain size and crystal orientation. As a result, we identify a molecular layer of flat-lying DNTT molecules at the semiconductor-insulator interface. It is likely that such a layer might form in other material systems as well, and could be one of the factors reducing charge transport. Controlling this interfacial flat-lying layer may raise the ultimate possible device performance for thin film devices.

Keywords: AFM; DNTT; GIXD; NEXAFS; vacuum evaporation

Publication Types

• Journal Article
• Research Support, Non-U.S. Gov't