This is an old revision of the document!
This tutorial is based on the following publication.
[Fathololoumi2012]
Terahertz quantum cascade lasers operating up to ~200 K with optimized oscillator strength and improved injection tunneling
S. Fathololoumi, E. Dupont, C.W.I. Chan, Z.R. Wasilewski, S.R. Laframboise, D. Ban, A. Mátyás, C. Jirauschek, Q. Hu, H. C. Liu
Optics Express 20, 3866 (2012)
This article describes an AlGaAs/GaAs THz quantum cascade laser (QCL) operating at around 2.6 to 3.22 THz.
The corresonding input file is called
THz_QCL_GaAs_AlGaAs_Fathololoumi_OptExpress2012_10K-MEDIUM.xml
.
Note that we also provide an input file called
THz_QCL_GaAs_AlGaAs_Fathololoumi_OptExpress2012_10K-FAST.xml
which is faster but does not produce accurate result.
This “fast” file is only intended to show the user how to run a “quick” simulation.
The results shown here correspond to the “medium” file.
We simulate the structure at a temperature of 10 K.
<Temperature unit="K"> 10 </Temperature>
First, the well and barrier materials have to be defined.
<Material_Well> <name> GaAs </name> <!-- GaAs --> </Material_Well> <Material_Barrier> <name> Al(x)Ga(1-x)As </name> <!-- Al(x)Ga(1-x)As --> <Alloy_Composition> 0.15 </Alloy_Composition> <!-- x, i.e. Al0.15Ga0.85As --> </Material_Barrier>
Then, alternating layers consisting of barrier and well have to be specified.
<Layer> <!-- #1 --> <Barrier_Thickness unit="nm"> 4.1 </Barrier_Thickness> < Well_Thickness unit="nm"> 16.0 </ Well_Thickness> </Layer> <Layer> <!-- #2 --> <Barrier_Thickness unit="nm"> 4.3 </Barrier_Thickness> < Well_Thickness unit="nm"> 8.9 </ Well_Thickness> </Layer> <Layer> <!-- #3 --> <Barrier_Thickness unit="nm"> 2.46 </Barrier_Thickness> < Well_Thickness unit="nm"> 8.15 </ Well_Thickness> </Layer>
(Discuss the doping here.)
(Discuss the potential drop per period here.)
(Discuss chosen masses and band offsets.)
<Material_Parameters> <Band_Offset unit="meV"> 120 </Band_Offset> <Effective_Mass_Well unit="m0" > 0 </Effective_Mass_Well> <Effective_Mass_Barrier unit="m0" > 0 </Effective_Mass_Barrier> </Material_Parameters>
(Plot and discuss gain results.)