An improved performance of copper phthalocyanine OFETs with channel and source/drain contact modifications

We report an effective method to improve the performance of p-type copper phthalocyanine (CuPc) based organic field-effect transistors (OFETs) by employing a thin para-quaterphenyl (p-4p) film and simultaneously applying V₂O₅ to the source/drain regions. The p-4p layer was inserted between the insulating layer and the active layer, and V₂O₅ layer was added between CuPc and Al in the source–drain (S/D) area. As a result, the field-effect saturation mobility and on/off current ratio of the optimized device were improved to 5 × 10⁻² cm²/(V·s) and 10⁴, respectively. We believe that because p-4p could induce CuPc to form a highly oriented and continuous film, this resulted in the better injection and transport of the carriers. Moreover, by introducing the V₂O₅ electrode's modified layers, the height of the carrier injection barrier could be effectively tuned and the contact resistance could be reduced. (paper)