HgCdTe-based quantum cascade lasers operating in the GaAs phonon Reststrahlen band predicted by the balance equation method.

The lack of radiation sources in the frequency range of 7-10 THz is associated with strong absorption of the THz waves on optical phonons within the GaAs Reststrahlen band. To avoid such absorption, we propose to use HgCdTe as an alternative material for THz quantum cascade lasers thanks to a lower phonon energy than in III-V semiconductors. In this work, HgCdTe-based quantum cascade lasers operating in the GaAs phonon Reststrahlen band with a target frequency of 8.3 THz have been theoretically investigated using the balance equation method. The optimized active region designs, which are based on three and two quantum wells, exhibit the peak gain exceeding 100 cm