Room-temperature operation of InGaAs/AlInAs quantum cascade lasers grown by metalorganic vapor phase epitaxy

We report the room-temperature operation of λ≈8.5 μm InGaAs/AlInAs quantum cascade lasers, grown by low-pressure metalorganic vapor phase epitaxy. The necessary control of interfacial abruptness and layer thicknesses was achieved by the use of individually purged vent/run valves and a growth rate of 0.8 μm/h for the active region. Low-temperature threshold current densities of ∼1.5 kA cm−2 and a maximum operating temperature of 290 K have been measured in pulsed operation. These values are comparable with those reported for structures of a similar design grown using molecular beam epitaxy.