Study of the Performance Enhancement of MoO₃/Au Bilayer Source–Drain Electrode for Top-Contact Pentacene-Based OTFT

To achieve an improved and low-cost pentacene-based organic thin-film transistor (OTFT), we fabricated three sets of OTFT devices with a MoO₃ transition metal oxide layer at the pentacene/electrode interface using a Au metal electrode. Among these devices, one device contains a single source–drain metal electrode, and in the other two devices, we inserted the MoO₃ layer. We used MoO₃ material in two different forms: one is a commercially available form (laboratory-prepared pure MoO₃, purchased from Sigma-Aldrich), and the other is oxidized MoO₃ which we prepared by oxidizing Mo filament by thermal evaporation in our laboratory. We found that the oxidized MoO₃/Au bilayer source–drain electrode OTFT device exhibits better performance than the other OTFT devices we fabricated with a laboratory-prepared pure MoO₃/Au bilayer source–drain electrode combination. The estimated device parameters of the oxidized MoO₃/Au bilayer source–drain electrode OTFT including field-effect mobility, on/off ratio, threshold voltage and sub-threshold slope are 1.7 cm²v⁻¹s⁻¹, 2.5 × 10⁶, −3.5  V and 0.39 V/decade, respectively.