Temperature dependence of thermal conductivity and boundary resistance in THz quantum cascade lasers

We measured the lattice temperature (T-L) distribution, the cross-plane thermal conductivity (k(perpendicular to)), and the thermal boundary resistance (TBR) of the GaAs/Al0.15Ga0.85As quantum cascade lasers (QCLs) operating at 2.83 THz in the heat sink temperature range 45-300 K. This information was extracted from the analysis of microprobe hand-to-hand photoluminescence in QCLs operating in continuous wave. Both k(perpendicular to) and TBR decrease monotonically at increasing temperature, the main influence on k(perpendicular to) arising from the high density of interfaces.