TUTORIALS
ATOMISTIC SIMULATION OF A RANDOM ALLOY InGaN/GaN QW
TUTORIALS

This example performs the simulation of a InGan/GaN Quantum Well (QW) structure by employing the new Empirical Tight Binding (ETB) Module on a relaxed atomic structure.

After defining an atomistic structure corresponding to the quantum cluster where we want to apply ETB calculations, we begin with continuous simulations on the whole device structure.

We first perform elasticity calculations to obtain the strain tensor in the heterostructure and to apply a strain deformation to the defined atomistic structure.
This result provides a reasonable first guess for the valence force field (VFF) solver, which will yield the final relaxed structure.

We then perform the drift-diffusion model to get the equilibrium solution for potentials and band profiles.

Quantum ETB calculations are finally performed on the VFF-relaxed structure, to get the electron and hole states in the QW.

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Atomistic simulation with ETB: InAs QW
TUTORIALS

This example performs the simulation of a InAs/GaAs Quantum Well (QW) structure by employing the new Empirical Tight Binding (ETB) Module

After defining an atomistic structure corresponding to the quantum cluster where we want to apply ETB calculations, we begin with continuous simulations on the whole device structure.

We first perform the drift-diffusion model to get the equilibrium solution for potentials and band profiles. Then quantum ETB calculations are performed to get the electron and hole states in the QW.

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TIGHT-BINDING SIMULATION OF A GaN QUANTUM DOT
TUTORIALS

In this Tutorial we will see how to perform the simulation of a GaN/AlN Quantum Dot (QD) structure by employing the Empirical Tight Binding (ETB) Module.

We first define an atomistic structure corresponding to the quantum cluster where we want to apply ETB calculations, than we apply continuous simulations on the whole device structure, in order to calculate strain map and equilibrium solution for potentials in device.

Then quantum calculations are performed with empirical_tb Module to get the electron and hole states in the QD.

The device structure is defined in the geometry .geo file and is the following:
a spherical GaN QD with radius 1 nm inside a 5X5 nm AlN cubic region

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GaN NANOWIRE LED WITH InGaN QUANTUM DISK
TUTORIALS

This example performs 3D simulation of a GaN Nanowire (NW) LED with an embedded InGaN quantum disk (QD).

We first perform a strain simulation, to get deformation potentials and piezoelectric polarization, than we apply drift-diffusion model with an increasing bias to the contacts, until the nanocolumn diode is brought in conduction regime. Then quantum efa calculations are performed to get the electron and hole states in the QD.

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N-CHANNEL MOSFET
TUTORIALS

In this tutorial we will show an example of 2D simulation of a Si n-MOSFET device.
We will calculate:


In order to execute correctly the example you should have the following files in the working directory:


For a detailed tutorial of the geometrical modelling with GMSH, see Getting started 2 »

Here is the geometry of the Mosfet device as it is meshed by GMSH.

Meshed Geometry


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SCHROEDINGER-POISSON-DRIFT DIFFUSION SIMULATION OF A QUANTUM WELL
TUTORIALS

In this tutorial we will see an example of self-consistent calculation of Poisson-Driftdiffusion model together with EFA Schroedinger calculations (through the Modules efaschroedinger and driftdiffusion).
First we will bring a AlGaAs /GaAs quantum well based pn-diode to a bias point where energy levels in the well are suitable populated; then we will calculate the self consistent charge density in the GaAs quantum well.
A predictor-corrector method is applied to improve the convergence of the self-consistence cycle.

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Si PN DIODE 1D
TUTORIALS

In this tutorial we will show a simple 1D Si pn diode example.
We will calculate the IV characteristic of the pn diode, by solving the Poisson equation and calculating the current with a drift-diffusion scheme.

The semi-classical transport simulation of electrons and holes is based on the driftdiffusion approximation.
Beside the electric potential, the electro-chemical potentials are used as variables such that the system of PDEs to be solved reads as follows:

equation 1

equation 2

equation 3

where P is the electric polarization due to e.g. piezoelectric effects and R is the net recombination rate, i.e. recombination rate minus generation rate.

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InGaAs QW 1D
TUTORIALS

In this tutorial we will see how to calculate quantum properties of a GaAs/InGaAs QW.
Schrödinger equation is solved, with a single-band effective mass model for conduction band and with a 6 band-kp model for valence band. Eigenvalues and eigenfunctions are calculated to get energy levels and wavefunctions in the quantum well.
Simulation is performed at equilibrium, and first a strain calculation for the GaAs/InGaAs/GaAs heterostructure, with GaAs as a reference substrate, is performed.

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