Tool: nextnano++
 Tool: nextnano

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nextnano3 - Tutorial

next generation 3D nano device simulator

1D Tutorial

HEMT structure (High Electron Mobility Transistor)

Authors: Stefan Birner

-> / * - input file for the nextnano3 and nextnano++ software (1D simulation)

These input files are included in the latest version.

HEMT structure

  • This input file simulates a HEMT structure:
  • It consists of:

    at    10 nm: Schottky barrier of 0.2 eV
    10 - 20 nm: In0.532Ga0.468As
    20 - 45 nm: Al0.477In0.523As
    45 - 95 nm: In0.532Ga0.468As
    95 - ... nm: Al0.477In0.523As
    The structure is grown on InP. There is no strain as everything is lattice matched. (Nevertheless, we still calculate the strain.)

  • Now we add at x = 35 nm a silicon delta doping of 4.5 * 1012 cm-2 which leads to band bending.
    Instead of choosing a delta doping we specify a constant doping of 1.5 * 1020 cm-3 that extends over 0.3 nm.
    (1.5 * 1020 cm-3 * 3 * 10-8 cm = 4.5 * 1012 cm-2)



    We obtain two eigenstates and their corresponding wave functions inside the HEMT channel which leads
    to a two-dimensional electron gas (2DEG). The electron density is plotted in blue.

  • In the file densities/int_el_dens1D.dat we can find the integrated density in each region cluster.
    The total integrated density (from 10 nm to 100 nm) which can be measured experimentally is thus
    2.19 * 1012 cm-2 in agreement with the experiment. Most of the density is located between 45 nm and 95 nm, namely 2.05 * 1012 cm-2.


2D/3D simulations


Input files for the same HEMT structure as in 1D, but this time for a 2D and 3D simulation are also available.
==> 2D: rectangle of dimension 250 nm x 10 nm
==> 3D: cuboid     of dimension 250 nm x 10 nm x 10 nm

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