Design and simulation of deep-well GaAs-based quantum cascade lasers for 6.7 μm room-temperature operation

We present the design and simulation of a GaAs-based quantum cascade laser (QCL) emitting at 6.7 mu m, the shortest room-temperature lasing wavelength projected to date for GaAs-based QCLs. This is achieved by introducing compressive strain only in the active quantum wells, where the optical transition occurs. A Monte Carlo simulation including both Gamma- and X-valley transport demonstrates that the proposed QCL achieves room-temperature lasing at a threshold-current density of 14 kA/cm(2), lower than that of the conventional 9.4 mu m QCL (16.7 kA/cm(2)). Furthermore, the electron temperature at 300 K lattice temperature is similar to that of the 9.4 mu m device. (C) 2007 American Institute of Physics.