The Effects of Electron Temperature in Terahertz Quantum Cascade Laser Predictions

Quantum cascade lasers (QCL's) employ the mid- and far-infrared intersubband radiative transitions available in semiconducting heterostructures. Through the precise design and construction of these heterostructures the laser characteristics and output frequencies can be controlled. When fabricated, QCL's offer a lightweight and portable alternative to traditional laser systems which emit in this frequency range. The successful operation of these devices strongly depends on the effects of electron transport. Studies have been conducted on the mechanisms involved in electron transport and a prediction code for QCL simulation and design has been completed. The implemented approach utilized a three period simulation of the laser active region. All of the wavefunctions within the simulation were included in a self-consistent rate equation model. This model employed all relevant types of scattering mechanisms within three periods. Additionally, an energy balance equation was studied to determine the temperature of electron distributions separately from the lattice temperature. This equation included the influence of both electron-LO phonon and electron-electron scattering. The effect of different modelling parameters within QCL electron temperature predictions will be presented along with a description of the complete QCL prediction code.
Presented at the Modeling and Simulation for Defense Systems and Applications V, SPIE Vol 7705, held in Bellingham, WA, Apr 2010. Prepared in cooperation with University of Massachusetts, Lowell, MA.