Bias-induced doping engineering with ionic adsorbates on single-walled carbon nanotube thin film transistors

Abstract

Doping control on carbon nanotubes (CNTs) is a crucial step for implementation in future nanodevices. Chemical doping of CNTs is typically done via functionalization. Controlling the dopant types and position on the CNT-based thin film transistors (TFTs) and their stability has been a considerable challenge. Here, we report a CNT doping strategy utilizing ionic adsorbates controlled via gate and drain bias. Dopant type was controlled by the polarity of the gate bias, and positioning of the adsorbates was expedited by applying drain and gate bias. This enabled us to control n- or p-type doping that leads to drain-to-source or source-to-drain direction of Schottky diodes. The combined adsorbate-associated biasing method also allowed a selective dissociation of metallic channels to improve TFT on/off performance. Our approach demonstrates a practical means of fabricating CNT-based random network TFTs with deliberate doping and high stability under ambient conditions.