Theory Study Of Semiconductor QCL And Design Of Active Region Construture

At present, the output wavelength of the quantum cascade laser has been increased from mid infrared to terahertz band. It has an important application prospect in many scientific fields. In this paper, the comprehensive and in-depth study of semiconductor QCL active region structure design, output characteristics and performance evaluation by theoretical study of quantum cascade laser, designs two types of QCL new structures they are "diagonal transition" mode and "vertical transition" mode which based on InGaAs/InAl As and GaAs/GaAsAl material system. The output characteristics of designed structure has been analyzed and compared with references. The calculation results of this work provide an rich theoretical basis for the output performance optimization of semiconductor QCL.1. The solution of the one-dimensional Schrodinger equation satisfied by electrons in the conduction band of the sub levels by the MATLAB software using the FDTD method and transfer matrix method, and come to the each sub level positions and their corresponding wave function distributions. The existing active region of the semiconductor QCL is simulated, proving the method is verified.2. Construction of the performance evaluation system for semiconductor QCL, such as dipole matrix element, scattering time, threshold gain, threshold current density, external differential quantum efficiency and temperature, enrich the design theory of semiconductor QCL.3. The output characteristic of the new type of semiconductor QCL active region structure design is better than the same type of references, and "vertical transition" mode is better than "diagonal transition" mode. At room temperature, its output power is about 140 mW which bases on In0.53Ga0.47As/In0.52Al0.48As’ s "vertical transition" structure.