Ellipsometric study and application of rubrene thin film in organic Schottky diode

Rubrene thin film was deposited by thermal evaporation technique under high vacuum (∼10−4 Pa). The film surface morphology was characterized by atomic force microscopy (AFM). Ellipsometric studies on rubrene thin film were presented for understanding its growth and optical characteristics by the Classical-Oscillator model. The analysis of the absorption coefficient (α) revealed the direct allowed transition with corresponding energy 2.21 eV of the rubrene film. In order to exploring the rubrene applications, Al/rubrene/ITO Schottky diode was fabricated. The basic device parameters, barrier height and ideality factor were determined by the I-V measurement. The log(I)-log(V) characteristic indicated three distinct regions. These regions followed ohmic conduction, TCL conduction and SCLC conduction mechanisms.