Scaling analysis of electron transport through metal-semiconducting carbon nanotube interfaces: Evolution from the molecular limit to the bulk limit

Abstract

We present a scaling analysis of electronic and transport properties of metal-semiconducting carbon nanotube interfaces as a function of the nanotube length within the coherent transport regime, which takes fully into account atomic-scale electronic structure and three-dimensional electrostatics of the metal-nanotube interface using a real-space Green's function based self-consistent tight-binding theory. As the first example, we examine devices formed by attaching finite-size single-wall carbon nanotubes (SWNT) to both high- and low- work function metallic electrodes through the dangling bonds at the end. We analyze the nature of Schottky barrier formation at the metal-nanotube interface by examining the electrostatics, the band lineup and the conductance of the metal-SWNT molecule-metal junction as a function of the SWNT molecule length and metal-SWNT coupling strength. We show that the confined cylindrical geometry and the atomistic nature of electronic processes across the metal-SWNT interface leads to a different physical picture of band alignment from that of the planar metal-semiconductor interface. We analyze the temperature and length dependence of the conductance of the SWNT junctions, which shows a transition from tunneling- to thermal activation-dominated transport with increasing nanotube length. The temperature dependence of the conductance is much weaker than that of the planar metal-semiconductor interface due to the finite number of conduction channels within the SWNT junctions. We find that the current-voltage characteristics of the metal-SWNT molecule-metal junctions are sensitive to models of the potential response to the applied source/drain bias voltages.

Minor revision to appear in Phys. Rev. B. Color figures available in the online PRB version or upon request to: [email protected]

References in corpus (14)

• Carbon Nanotubes as Schottky Barrier Transistors
• Quantum Transport in Semiconductor Nanostructures
• Tuning carbon nanotube bandgaps with strain
• Electron-Phonon Scattering in Metallic Single-Walled Carbon Nanotubes
• High-Field, Quasi-Ballistic Transport in Short Carbon Nanotubes
• Microscopic study of electrical transport through individual molecules with metallic contacts: I. "Band" lineup, voltage drop and high-field transport
• Probability of anomalously large Bit-Error-Rate in long haul optical transmission
• Microscopic study of electrical transport through individual molecules with metallic contacts: II. Effect of the interface structure
• Lateral scaling in carbon nanotube field-effect transistors
• Electrical Nanoprobing of Semiconducting Carbon Nanotubes using an Atomic Force Microscope
• End group effect on electrical transport through individual molecules: A microscopic study
• Transport through the Interface between a Semiconducting Carbon Nanotube and a Metal Electrode
• Scaling analysis of Schottky barriers at metal-embedded semiconducting carbon nanotube interfaces
• Schottky barriers at metal-finite semiconducting carbon nanotube interfaces

Cited by in corpus (4)

• Metal contacts in carbon nanotube field effect transistors: Beyond the Schottky barrier paradigm
• Bias-driven local density of states alterations and transport in ballistic molecular devices
• Electron transport in semiconducting carbon nanotubes with hetero-metallic contacts
• Band gap engineering in finite elongated graphene nanoribbon heterojunctions: Tight-binding model