Ambipolar Transistors with Heterostructures of Single-Walled Carbon Nanotubes and Zinc Tin Oxide

The unique operation of ambipolar thin-film transistors (TFTs), in which both electrons and holes can be injected and transported in a single device, have attracted significant attention since it was first demonstrated in mid-1990s. In addition to their unique operation, these devices have great potential in complementary-like circuits and novel light emitting transistors. Single-walled carbon nanotubes (SWCNTs) exhibit ambipolar behavior intrinsically; however, SWCNTs under ambient conditions show strong p-type behavior due to adsorption of oxygen and moisture from air. In this work, we will discuss the performance characteristics of ambipolar TFTs with heterostructures of a network of SWCNTs and amorphous zinc tin oxide. These TFTs exhibit well-balanced electron and hole mobilities under ambient conditions, and both carriers are injected through Ti/Au contacts without large injection barriers. Charge transport in this material system will be described. In addition, complementary-like inverters which are composed of two ambipolar TFTs will be demonstrated.