Pentacene Thin Film by Compact Thermal Evaporation System

A compact thermal evaporation technique was used to fabricate pentacene thin films from a pure (99%) powder. All of the samples were grown at ambient temperature on glass substrates coated with indium tin oxide (ITO), and their optical, structural, and electrical properties were investigated. UV-visible (UV-Vis) spectroscopy and photoelectron spectroscopy in atmosphere (PESA) methods were used to evaluate the optical properties of a pentacene thin film utilising experimental values of optical band gap and ionisation potential. The energy band diagram of the highest occupied molecular orbital - lowest unoccupied molecular orbital (HOMO-LUMO) level depicts the electronic structure of pentacene. The HOMO and LUMO energy levels were determined toward being -5.49 eV and -3.74 eV, respectively, while the optical bandgap was 1.75 eV. Then, X-ray diffraction (XRD) was used to examine the structural properties of a thermally evaporated pentacene thin film. The XRD analysis revealed the bulk phase thin films oriented along the (001) plane direction. Finally, metal/pentacene/metal structured device was fabricated and showed a rectifying behavior.

Automated summary

A compact thermal evaporation technique was utilized to fabricate pentacene thin films, and their optical, structural, and electrical properties were investigated. The energy band diagram revealed the electronic structure of pentacene, and XRD analysis showed the films oriented along the (001) plane direction. Furthermore, a metal/pentacene/metal structured device exhibited rectifying behavior.