The authors report on the systematic characterization of structural effects of organic complementary inverters based on two -conjugated organic molecules, pentacene and copper hexadecafluorophthalocyanine (F16CuPc). Three classes of inverters with different layered structures in top-contact configuration were produced using the neutral cluster beam deposition method. Their voltage transfer characteristics, gain curves and hysteresis behaviour were characterized with respect to their thickness. Class I inverters, with generic structures of single-layered, p-and n-type (200/180) transistors, exhibited high gains of 12.8 ± 1.0 with sharp inversions. Their two constituent transistors, with hole and electron mobilities of 0.38 cm 2 V-1 s-1 and 7.0 × 10-3 cm2 V-1 s-1, respectively, showed well-coupled carrier conduction during operation. The behaviour of class II and III inverters, with layered heterojunction structures, was independent of upper-layer thickness and did not show hysteresis. The better performances of class II inverters, which showed high gains of 14.4 ± 1.1, were rationalized partly in terms of decreased mobility differences between their constituent transistors. Heterojunction geometries can be applied to obtain high-performance, fast-switching inverters by avoiding direct exposure of the air-sensitive transistors to ambient conditions. The inverters' general operating conduction mechanism is also discussed.
ASJC Scopus subject areas
- Condensed Matter Physics
- Electronic, Optical and Magnetic Materials
- Acoustics and Ultrasonics
- Surfaces, Coatings and Films