Carrier Recombination, Long-Wavelength Photoluminescence, and Stimulated Emission in HgCdTe Quantum Well Heterostructures

Interband photoluminescence (PL) and stimulation emission (SE) from HgTe/HgCdTe quantum well (QW) heterostructures are studied in 5-20 mu m wavelength range in regard to long-wavelength lasing applications. The authors obtain carrier lifetimes using time-resolved photoconductivity measurements and show that the dominating mechanism of carrier recombination changes from the radiative process to the non-radiative one as the bandgap is decreased, limiting the operating temperature for SE. The authors suggest that decreasing the QW width should reverse the balance in carrier recombination in favor of radiative processes and demonstrate 75?K improvement in the operating temperature in structure with narrower QW.