The Study Of Mid-infrared InAs/GaInSb Interband Cascade Lasers

In this article, I have investigated the quantum cascade laser(QCL), it bases on one type of carrier(electrons) making transitions between sub-energy levels in conduction band, the energy levels are created by quantum confinement. This quantum cascade laser is not limited by the Auger recombination which is typical in interband III-V and II-VI diode lasers. This laser uses cascade structures, it can get higher quantum efficiency, it can provide a higher mid- infrared powers at higher temperatures with a weak tempera- ture dependence of the threshold current, and this laser can have a better performance.In this thesis, I have gived the development of this laser by translating a lot of English literatures,and I have discussed the material systems which form the laser struc- ture, for example: InP/GaInAs/AlInAs, GaAs/AlGaAs, GaInAs/ AlAsSb, InAs/AlSb, using strain-compensated GaInAs/AlInAs on InP substrate,the quantum cascade laser can emit wave- length below 4μm,growing lattice matched GaInAs/AlAsSb on InP substrate and basing on InAs/AlSb material system make the quantum cascade lasers emit wavelength in the mid- infrared spectrum region,these two types of the quantum cascade lasers have a great development, However,this Sb-based material system is not so well studied as InP and GaAs-based systems, by studying this system further more, optimizing structure design and extension method,we can increase the working temperature of the quantum cascade laser,and reduce its threshold current density,improve the device performance.In this treatise, I have studied another new type of mid- infrared semiconductor laser, interband cascade laser (ICL), this laser reuses each injected electron by taking advantage of the broken bandgap alignment in Sb-based type-II quantum wells to form cascade stages, leading to a greater quantum efficiency, similar to the intersubband quantum cascade laser. Furthermore, this IC lasers can circumvent the fast phonon scattering loss in intersubband quantum cascade lasers and suppress Auger recombination through optimizing device structure and band-structure engineering. Thus, mid-IR interband cascade lasers are promising for obtaining high output power.In this paper,I have designed an interband cascade laser,it bases on InAs/GaInSb type-II quantum wells,it contains 10 repeated active regions,the designed emitting wavelength is around 3.5μm,this laser is grown on n-GaSb substrate,the two n-doped InAs/AlSb superlattices act as top and bottom claddings,they can limit the laser beam in this region. Using Crosslight simulation software to simulate, I use the Layer3D program to grow the layer structure, set the layer parameter,for example,the thickness and length of the layer,the active InAs/GaInSb material constitute,doping types and densities,contact electrode and so on. By giving some beginning parameters, I use EasySimulation program to start the simulation, and I get the laser's simulation results, using CrosslightView program, I get some character- ristic curves, and I give detailed analysis and discussions to these characteristic curves, for example, the emitting wavelength vs current characteristic, peak output power vs current, peak gain vs current characteristic, and I-V characteristic.Conclution, from the simulation results, we can see this interband cascade laser's emitting wavelength is around 3.52μm, threshold current density is about 566.7A/cm2, the maximum output power is 27mW, and the external quantum efficiency is nearly 45%.