Effect of access resistance on the experimentally measured temperature-carrier mobility dependence in highly-crystalline DNTT-based transistors

Carrier mobility extraction is easily influenced by contact resistance, especially in transistors with a high carrier mobility and a short channel length, which would obscure the investigation into charge transport in organic field-effect transistors (OFETs). Here, we perfunctorily observe a positive carrier mobility-temperature relationship (partial derivative mu/partial derivative T > 0) and a temperature-independent carrier mobility (partial derivative mu/partial derivative T = 0) in OFETs based on less- and highly-crystalline DNTT bulk films, respectively, while their room-temperature carrier mobilities are almost identical. The difference in the temperature-carrier mobility dependence is attributed to the influence of access resistance while the active channels at the semiconductor/dielectric interface were deposited by the same process of different evaporation rates, which leads to different contact resistances tuned by the DNTT molecular packing in the c-axis. Therefore, it will be beneficial for investigating the charge transport of organic semiconductors by eliminating the influence of access resistance in staggered OFETs.