In situ ultraviolet photoemission spectroscopy measurement of the pentacene-RuO2/Ti contact energy structure

Abstract

In situ ultraviolet photoemission spectroscopy was used during the pentacene layer growth on ruthenium and ruthenium oxide films to measure the energy barrier in the metal-semiconductor contact. The measurement showed that ruthenium oxide film formed lower hole-injection barrier with pentacene than ruthenium or gold metal film due to its high work function of 4.92 eV and low resistivity of similar to 350 mu Omega cm. Pentacene thin film transistor with ruthenium oxide electrode showed higher mobility of 0.435 cm(2)/V s and on-off ratio of 106 than ruthenium (mu : 0.205 cm(2)/V s, on/off ratio: 10(6)) or gold electrode (mu : 0.338 cm(2)/V s, on/off ratio: 10(6)) of the same structure. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3481084]