Abstract
With aluminum (Al) source–drain electrodes, the transfer characteristics of pentacene-based organic field-effect transistors (OFETs) change from ambipolar to n-type after 24h of storage in a nitrogen-filled glove box Chang et al. (2011) [16]. The time-dependent decrease of hole current is associated with the interfacial reaction at the Al source–drain electrodes and pentacene, which was studied by in-situ ultraviolet photoemission spectroscopy and X-ray photoelectron spectroscopy in this work. Experimental results indicate that the interface of the Al and pentacene is partially oxidized, but the similar oxidation was not observed at the interface of the pentacene and silver. The time-dependent oxidization of Al and pentacene creates an interfacial barrier to suppress the hole injection from Al electrodes (extraction of electrons from pentacene). However, it shows minor effect in the injection of electrons from Al electrode. Since the rate of oxidation is related to the contact area of the pentacene and Al, co-evaporating a thin Al:pentacene interlayer between the pentacene and Al electrodes expands the contact surface and accelerates the reaction, which is suitable for the fabrication of n-type only pentacene-based OFETs. This study highlights the impact of the interfacial reaction in Al/pentacene interface for the transformation of ambipolar to n-type OFETs.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.