Simulates ballistic transport properties in 3D Carbon NanoTube Field Effect Transistor (CNTFET) devices

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Published on 08 May 2008 All versions

doi:10.4231/D3BK16P2W cite this



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CNTFET can currently simulate the impact of quantum mechanical size quantization and phase coherence in zigzag nanotubes with both planar and coaxial exterior architectures. The application is based on the Non-Equilibrium Greens’ Function (NEGF) techniques using a pz-orbital nearest-neighbor tight binding. Full three-dimensional (3D) electrostatics has been captured by the Finite-Element-Method (FEM) of solving the Poisson Equation. Solution of this set of equations is computationally expensive. One can reduce the simulation time by using a mode-space approach instead of the real-space approach. By default the simulator solves for both electrons and holes, although one may activate electron-transport only. The numerical problem consists in computing the diagonal elements of the matrix Gr = [ EI - H - ]-1 (retarded Green’s function) and G< = G∑<G (electron correlation Green’s function), where E is the energy level, H is the device Hamiltonian matrix, and and < are self energies († denotes the transpose conjugate of a matrix). The algorithmic flow is based on Dyson’s equation solved through recursive Green’s function approach. Developed at Purdue University, CNTFET has been parallelized with Message Passing Interface (MPI) and ported to various computing platforms. The MPI is applied in the integration procedure to calculate the charge density over the energy spectrum while the Green’s function at each energy point is calculated by a serial algorithm.


CNTFET has been developed at Purdue University, West Lafayette, IN, USA. More information on CNTFET can be found by contacting Neophytos Neophytou or Shaikh S. Ahmed.

Cite this work

Researchers should cite this work as follows:

  • Neophytos Neophytou, Shaikh Ahmed, Gerhard Klimeck, "Non-Equilibrium Green’s Function (NEGF) Simulation of Metallic Carbon Nanotubes: The Effect of the Vacancy Defect," Journal of Computational Electronics, in press (2007).

  • Neophytos Neophytou, Jing Guo, Mark Lundstrom, "Three-dimensional electrostatic effects of carbon nanotube transistors," IEEE Transactions on Nanotechnology 5, 385 (2006).

  • Neophytos Neophytou; Shaikh S. Ahmed; POLIZZI ERIC; Gerhard Klimeck; Mark Lundstrom (2016), "cntFET," (DOI: 10.4231/D3BK16P2W).

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