Effect of SOCl2 doping on electronic properties of single-walled carbon nanotube thin film transistors

We report on SOCl2 doping of separated single‐walled carbon nanotubes (SWCNTs) having different properties (metallic, semiconducting, and mixed). SWCNTs were doped by dropping SOCl2 on a percolated network which was prepared on a Si substrate and the doping effect was evaluated by measuring electrical characteristics. Pristine semiconducting SWCNTs showed p‐type transfer characteristics. After SOCl2 doping, the conductivity of semiconducting SWCNTs increased about two times and the on/off ratio decreased by a factor of 3. Mixed pristine samples showed slight p‐type characteristics and turned to metallic characteristics after doping. The network of metallic SWCNTs did not show any significant change of conductivity before and after doping.