Temperature Dependence of Barrier Height and Performance Enhancement of Pentacene Based Organic Thin Film Transistor with Bi-Layer MoO3/Au Electrodes

We investigated top-contact pentacene-based organic thin-film transistor (OTFTs) with bi-layer MoO3/Au electrodes. The device performance including field effect mobility, threshold voltage, and On/Off ratio was highly improved in a device with 5 nm MoO3 layer which showed the highest field-effect mobility of 0.72 cm(2) V(-1)s(-1). In addition, from temperature dependence characteristics, we observed that the barrier height was dramatically decreased from 0.12 eV (without MoO3) to 0.03 eV in device with 5 nm MoO3 layer. This improved device performance was attributed to significant reduction in barrier height at Au/pentacene interfaces and surface roughness of pentacene layer after inserting a suitable MoO3 layer between pentacene and gold electrodes.