Carrier Lifetimes of Iodine-Doped CdMgTe/CdSeTe Double Heterostructures Grown by Molecular Beam Epitaxy

Iodine-doped CdMgTe/CdSeTe double heterostructures (DHs) have been grown by molecular beam epitaxy and studied using time-resolved photoluminescence (PL), focusing on absorber layer thickness of 2 μ m. The n -type free carrier concentration was varied to ∼7 × 10 15 cm −3 , 8.4 × 10 16 cm −3 , and 8.4 × 10 17 cm −3 using iodine as dopant in DHs. Optical injection at 1 × 10 10 photons/pulse/cm 2 to 3 × 10 11 photons/pulse/cm 2 , corresponding to initial injection of photocarriers up to ∼8 × 10 15 cm −3 , was applied to examine the effects of excess carrier concentration on the PL lifetimes. Iodine-doped DHs exhibited an initial rapid decay followed by a slower decay at free carrier concentration of 7 × 10 15 cm −3 and 8.4 × 10 16 cm −3 . The optical injection dependence of the carrier lifetimes for DHs was interpreted based on the Shockley–Read–Hall model. The observed decrease in lifetime with increasing n is consistent with growing importance of radiative recombination.