High frequency characterization of carbon nanotube and graphene materials

Carbon nanotube and graphene based materials and devices have been extensively studied since they were discovered and are considered as potential building blocks for nano-scale circuits in virtue of their unique mechanical, electrical and thermal properties. Numerous other potential applications in areas ranging from field emission displays, microscopy and scanning/tunneling microscope tips to fuel cells and batteries have been investigated. Many microwave and THz applications have been suggested as well recently, including nano-antennas and nano-interconnects. However, over the microwave and THz regimes, the electrical properties of CNTs are yet to be thoroughly investigated [1]. Characterizing the high frequency properties of these materials is rather difficult, mainly due to the nanometer sized samples and much larger wavelength associated with microwave and THz spectra [2]. In addition, one of the biggest obstacles for massive production of nanotube circuits is the difficulty of separating semiconducting tubes from metallic tubes [3].