Temperature dependent characteristics of λ∼3.8 μm room-temperature continuous-wave quantum-cascade lasers

Temperature dependent characteristics of lambda similar to 3.8 mu m quantum-cascade lasers (QCLs) operating up to 318 K in continuous-wave (cw) mode are reported. A high-reflectivity coated 11.5-mu m-wide and 4-mm-long epilayer-down bonded QCL using a diamond submount shows a considerable improved cw operation with an output power of 143 mW and a threshold current density of 1.51 kA/cm(2) at 298 K. The temperature dependence on optical and electrical performances of the QCLs with respect to the output power, slope efficiency, threshold current/voltage, turn-on voltage, differential series resistance, and emission wavelength are investigated systematically above liquid nitrogen temperature. (c) 2006 American Institute of Physics.