First-principles study of charge transport in interfaces based on carbon nanomaterials for device applications

Abstract

Recently, carbon nanomaterials have been expected to take a key role in future-generation elec-tronic devices, both as electrode and channel materials. However, understanding their electronic properties and transport characteristics at the inhomogeneous interfaces, which are major factor in determining device characteristics, are still lacking. By adopting the combination of density functional theory (DFT) and matrix Green’s function (MGF) calculations, this thesis paper presents theoretical studies on the interface charge transport properties of carbon nanomaterials-based junctions and novel ways to enhance device characteris-tics. In this context, this thesis paper covers two different problems involving carbon nanomaterials-based junction systems. First, we proposed a novel nanoelectromechanical switch (NEMS switch) mechanism of C60 chains based on their reversible oligomerization to achieve ultra-high on/off switching ratio. By controlling the interface parameters, we devised a new way to exploit change in electronic structure during the oligomeri-zation for device operations. Second, we reported a novel architecture of transverse tunneling DNA sequenc-ing device based on N-doped capped CNT which enables us with fast and reliable whole-genome sequencing. Using two different nanogap distances involving chemically functionalized carbon nanoelectrode and apply-ing statistical approach, we achieved dual-sensing mechanism of DNA exploiting both chemical and energetic sensitivity that has never been reported elsewhere. What has been observed throughout this paper would pro-vide the insight on controlling contact charge injection within carbon nanomaterial-based systems in general. Moreover, since the electric structures and the nature of chemical bonds of carbon nanostructures are similar to each other, the novel principles and architectures reported in this paper are applicable to other types of carbon nanomaterials such as graphene.