Numerical simulation of III-nitride lattice-matched structures for quantum cascade lasers

We present a comparison among GaN/AlGaN, GaN/InAlGaN, and GaAs/AlGaAs quantum cascade structures based on a Monte Carlo study of carrier dynamics, to highlight the improvements offered by nitride latticematched structures. We take into account the interactions of electrons with other electrons as well as LO-phonons. The results obtained from the Monte Carlo simulations are used to calculate the population inversion of each structure to determine its temperature dependence. This study shows that the nitride-based structures offer significantly improved high-temperature performance compared to the GaAs device, including the possibility of room-temperature operation. Furthermore, by virtue of its lattice-matched nature, the GaN/InAlGaN materials system can potentially enable the high-quality growth of thick quantum cascade structures without plastic relaxation, as a way to overcome the structural issues that have so far hindered the development of these devices with nitride semiconductors.