Lattice-Matched and Strain-Compensated Materials for Mid-Wave and Long-Wave Infrared Quantum Cascade Lasers

Abstract

This work reports the growth and characterization of lattice-matched (LM) and strain-compensated (SC) AlInAs/GaInAs/InP heterostructures for quantum cascade lasers (QCLs) emitting in the mid-wave infrared (MWIR) and long-wave infrared (LWIR) wavelength regions. Organometallic vapor phase epitaxy growth conditions such as temperature, growth rate, and V/III ratio were varied to establish a step-flow growth mode. Multiple-quantum-well structures with either (LM) or with SC compressive GaInAs quantum wells and tensile AlInAs barriers were grown to optimize QCL structure growth. Atomic force microscopy and high-resolution x-ray diffraction data indicate excellent structural quality materials for QCLs. LM LWIR QCLs at 9.6 μm have pulsed peak power as high as 2.5 W/facet and pulsed wall-plug efficiency of 5.4%, while SC MWIR QCLs at 4.8 µm have peak power of 1.7 W and 9.7% pulsed wall-plug efficiency. SC MWIR QCLs exhibit very low threshold current density of 0.8 kA/cm2.