The nextnano++ solver#
The nextnano++ tool is a Schrödinger-Poisson-current solver and simulates quantum wells, quantum wires, quantum dots, …
Features of nextnano++ include:
includes group IV materials (Si, Ge, SiGe) and all III-V materials, its ternaries and quaternaries;
the nitrides are available in the zinc blende and wurtzite crystal structure
flexible structures and geometries (1D, 2D and 3D)
fully quantum mechanical electronic structure, based on the 8-band \(\mathbf{k} \cdot \mathbf{p}\) model
strain, piezo- and pyroelectric charges
growth directions along [001], [011], [111], [211], … in short along any crystallographic direction
equilibrium and non-equilibrium, calculation of current close to equilibrium (semi-classical)
magnetic fields
About#
The nextnano++ tool is a console application that is run from within nextnanomat. Alternatively, it can be executed from the command line (Command line). The input file specifies the device that shall be simulated.
The input file specifies all properties of the device, such as geometry, material composition, grid, contacts,… Furthermore, it sets all parameters that are needed to define the program flow of nextnano++. The keywords that can be used for this purpose are defined in the syntax (Input syntax) of the input file.
The nextnano++ tool exports its results to a directory and in a certain format that have to be specified in the section (Simulation output) of the input file.
The nextnano++ installation package provides numerous input files (C:\Program Files\nextnano\2020_12_09\Sample files\nextnano++ sample files) that can be run with nextnanomat, to get familiar with the program.
All material properties that are needed for simulation are specified as material parameters in database files (database{ }), which are provided with the nextnano++ installation. The database covers a large amount of Zincblende-related …zb{} groups in database{ } (all III-V and diamond-type like Si, Ge, …), Wurtzite-related …wz{} groups in database{ } (GaN, AlN, InN, …) materials, and their alloys.
Free examples#
Basics of defining structures#
Simple simulations#
Getting Started#
- Getting Started
- Input file basics
- Hello world
- Finite periodic structures
- Constant doping
- Adding and replacing doping
- Doping functions
- Doping in heterostructure
- Variables
- Importing files
- Defining shapes in 2D and 3D simulations
- Interpolation of 2-component alloys
- Schottky barrier
- Surface charges
- Band gap of strained AlGaInP on GaAs substrate
- Solution of the Poisson equation for different charge density profiles
- Piezo- and Pyroelectric charges in GaN/AlN/GaN wurtzite heterostructure
- Piezoelectricity in wurtzite
- Electron transport in n-type silicon
- I–V characteristics of n-doped Si structure
- I–V characteristics of n-doped GaN single layer
- n-i-n Si resistor
Reference#
Tutorials#
Note
Tutorials under development are tagged as status:under_development. The input files are not present in any release yet, and it is not clear when they will be added.
Attention
Links to the tutorials and names of exemplary input files may change.
- Tutorials
- Harmonic Oscillator
- Infinite quantum well
- Triangular well
- Double quantum well
- Electron States in Quantum Boxes
- Orbitals of the hydrogen atom
- Landau levels of a bulk GaAs sample in a magnetic field
- Transmission (CBR)
- Dispersion in infinite superlattices: Minibands (Kronig-Penney model)
- k.p dispersion in bulk GaAs (strained / unstrained)
- k.p dispersion in bulk unstrained, compressively and tensely strained GaN (wurtzite)
- Energy dispersion of holes in a quantum well
- Exciton Binding Energy in an Infinite Quantum Well
- Excitonic absorption in an infinite quantum well
- p-n junction in the dark
- p-n junction under illumination
- Silicon MOS Capacitor
- Silicon MOSFET
- Subband occupations of 2DEG InGaAs/InAlAs HEMTs
- Topological Insulators
- Landauer conductance and conductance quantization: from quantum wires to quantum point contacts
- Transmission through a nanowire (CBR)
- Conductance of a quantum point contact (gated two-dimensional electron gas)
- Depletion of electrons in a two-dimensional electron gas (2DEG)
- Optical absorption for interband and intersubband transitions
- Resonant photoluminescence of InGaAs/GaAs QWs
- Non-resonant photoluminescence of GaAs/AlGaAs QWs
- Wurtzite GaN/AlN/GaN on Si(111)
- Transmission through a nanowire (CBR)
- How to control convergence
- How to set attributes in k_integration{} - integrating over the FBZ
- How to control energy grids
- Modeling Quantum Effects in Large Gated Systems
Examples#
Validation#
- Validation
- k.p dispersion in bulk unstrained ZnS, CdS, CdSe and ZnO (wurtzite)
- Electronic band structures of HgTe, CdTe, and of the alloy CdxHg1-xTe
- Electronic band structure of holes in a GaN/AlGaN QW
- Electronic band structures and phase transition in CdxHg1-xTe-based quantum well
- Electronic band structures and phase transition in CdxHg1-xTe-based modulation-doped quantum well
- Electronic band structure of tri-layer InAs/GaxIn1-xSb/InAs quantum well
- Electronic band structure of 2DHG in silicon inversion layers under pseudomorphic strain | 1D
- Electronic band structure of 2DHG in Si inversion layers under arbitrary stress | 1D
- Artificial quantum dot crystal - Superlattice dispersion (minibands)
- Modeling type-II superlattice using interface Hamiltonian within 8-band \(\mathbf{k} \cdot \mathbf{p}\) method
- Schrödinger-Poisson - a comparison to the tutorial file of Greg Snider’s code
- Si/SiGe MODQW (Modulation Doped Quantum Well)
- Two-dimensional electron gas in an AlGaN/GaN FET
- Strain effects in freestanding nitride nanostructures
- Optical absorption of an InGaAs quantum well | 1D
- SiGe QW excitonic absorption
- SiGe MQW QCSE electro-absorption modulator (EAM)
- Fock-Darwin states of a parabolic, anisotropic (elliptical) potential in a magnetic field
- Fock-Darwin states of parabolic, isotropic potential in a magnetic field
- Efficient method for the calculation of ballistic quantum transport - The CBR method (2D example)
- Scattering times for electrons in unbiased and biased single and multiple quantum wells