Type II Superlattice

Click to download Project and Documentation

The following tutorial is based on that paper:

Sprengel, Stephan, et al. "InP-based type-II quantum-well lasers and LEDs." IEEE Journal of Selected Topics in Quantum Electronics 19.4 (2013)

We create the GaInAs/GaAsSb superlattice structure on InP with the following geometry parameters

  • width of $Ga_{0.22}In_{0.78}As$ region is 4.6nm
  • width of $GaAs_{0.49}Sb_{0.51}$ region is 3.8nm

In order to simulate the structure we need to set periodic boundary conditions in the Global Parameters field.

The first defined material should be InP, it means it gets specified as substrate.

The SL is strained due lattice miss-match on the InP substrate. Which results the following band structure on figure 1.

Figure 1. Band structure

The carrier density can be calculated classically, quantum mechanically without k space dispersion(constant effective mass), and with k space dispersion.

The following Self consistent results are plotted on the following Figure 2, 3, 4.

Figure 2. Classical carrier density
Figure 3. Quantum mechanical carrier density without k space dispersion
Figure 4. Quantum mechanical carrier density with k space dispersion

At the interface in Figure 3 there is a jump of the carrier densities, it is due the different carrier effective masses, while on Figure 4, when correct k space dispersion is calculated it has no effect.

Figure 5. Envelope wavefunctions of different charge carriers in single band approach

The project file can be downloaded from here

  • physicswiki/semiconductors/typeiisldisp/type_ii_sl_disp.txt
  • Last modified: 2019/04/10 05:27
  • by zoltan.jehn