An Efficient Method for Quantum Transport Calculations in Nanostructures using Full Band Structure

Abstract

Scaling of semiconductor devices has reached a stage where it has become absolutely imperative to consider the quantum mechanical aspects of transport in these ultra small devices. In these simulations, often one excludes a rigorous band structure treatment, since it poses a huge computational challenge. We have proposed here an efficient method for calculating full three-dimensionally coupled quantum transport in nanowire transistors including full band structure. We have shown the power of the method by simulating hole transport in p-type Ge nanowire transistors. The hole band structure obtained from our nearest neighbor sp3s* tight binding Hamiltonian agrees well qualitatively with more complex and accurate calculations that take third nearest neighbors into account. The calculated I-V results show how shifting of the energy bands due to confinement can be accurately captured only in a full band full quantum simulation.

Additional simulations are being carried on to add to the results section, mainly to investigate band-to-band tunneling in low band gap semiconductors. The pre-print draft is however, complete from the perspective of the quantum transport method that we illustrate