Review on Optimization Methods of Carbon Nanotube Field-Effect Transistors

Carbon nanotube field-effect transistors (CNTFETs) have been considered as a replacement for, or complement to, future semiconductor devices due to high mobility, low defect structure, and intrinsic nanometer scale of carbon nanotubes (CNTs). The great superiority in performance for CNTFETs vis-a-vis state-of-the-art silicon devices has attracted an intense research effort to explore their application viability. Since the first CNTFET was fabricated, CNTFETs have experienced great advances at the device structure as well as device performance. Various methods had been attempted to optimize the devices. These methods can mainly be divided into four aspects: (1) Decrease the contact resistance between CNTs and metal electrodes; (2) Increase the tuning efficiency of gate voltage to CNT channels; (3) Shorten the CNT channel length; (4) Adopt the optimized device structure. This review will briefly summarize these methods and describe the device performances achieved with these methods. Representative researches and updated progress on the optimization methods of CNTFETs will be introduced. From the review, the advances in CNTFETs can be also learned in the rough.