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- | ====== Tutorial - THz GaAs/AlGaAs (Fathololoumi) ====== | ||
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- | ===== Summary ===== | ||
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- | This tutorial is based on the following publication. | ||
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- | ''[Fathololoumi2012]''\\ | ||
- | [[http://dx.doi.org/10.1364/OE.20.003866|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. | ||
- | |||
- | ===== Simulation details ===== | ||
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- | We simulate the structure at a temperature of 10 K. | ||
- | <code> | ||
- | <Temperature unit="K"> 10 </Temperature> | ||
- | </code> | ||
- | |||
- | |||
- | ==== Device definition ==== | ||
- | |||
- | First, the well and barrier materials have to be defined. | ||
- | |||
- | <code> | ||
- | <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> | ||
- | </code> | ||
- | |||
- | Then, alternating layers consisting of barrier and well have to be specified. | ||
- | |||
- | <code> | ||
- | <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> | ||
- | </code> | ||
- | |||
- | The resulting conduction band edge profile can be found in the file called ''Band-Edge_vs_position.dat''. | ||
- | This file includes the band bending due to the electrostatic potential. | ||
- | At a bias voltage of 54 mV per period, it looks as follows. | ||
- | |||
- | == Doping == | ||
- | //(Discuss the doping here.)// | ||
- | |||
- | == Electric field == | ||
- | //(Discuss the potential drop per period here.)// | ||
- | |||
- | == Material parameters == | ||
- | //(Discuss chosen masses and band offsets.)// | ||
- | |||
- | <code> | ||
- | <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> | ||
- | </code> | ||
- | |||
- | |||
- | == Gain == | ||
- | |||
- | //(Plot and discuss gain results.)// | ||