Cobalt phthalocyanine-based submicrometric field-effect transistors

Abstract

We present performance characteristics of nanoscaled cobalt phthalocyanine (CoPc)-based organic field-effect transistors (OFETs) as a function of channel length. We found a channel length range which maximizes the field effect mobility in a trade-off between the decrease in the number of organic grain boundaries and the increase of the electrode-organic contact region. Further reduction of channel length is limited by fringe currents, which lead to an increased off current and to a degradation of the sub-threshold slope. From this, we define an optimal channel length of 280 nm to 1 μm for applications in submicrometric CoPc-based OFETs. Our results are particularly relevant for the miniaturization of chemical sensing OFETs, where metal phthalocyanines have proven to be excellent candidates for the fabrication of the transistor channel.