Characterization and Modeling of Reduced-Graphene Oxide Ambipolar Thin-Film Transistors
Nicolò Lago, Marco Buonomo, Rafael C. Hensel, Francesco Sedona, Mauro Sambi, Stefano Casalini, Andrea Cester
Abstract
The rise of graphene as an innovative electronic material promoted the study and development of new 2-D materials. Among them, reduced graphene oxide (rGO) appears like an easy and cost-effective solution for the fabrication of thin-film transistors (TFTs). To understand the limits and possible application fields of rGO-based TFTs, a proper estimation of the device parameters is of extreme importance. In this work, liquid-gated ambipolar rGO-TFTs are characterized and a description of their working principle is given. Particular attention is paid toward the importance of the transistors’ OFF-state conductivity that was modeled as a resistance connected in parallel with the TFT. Thanks to this model, the main transistor parameters were extrapolated from rGO-TFTs with different levels of electrochemical reduction. The extracted parameters allowed understanding that rGO-TFTs have similar holes and electrons mobilities, and the more pronounced p-type behavior of the devices is due to a positive shift in the p-type and n-type threshold voltages.