Effects of Zinc and Tellurium Doping on Minority Carrier Recombination in Lattice-Matched and Lattice-Mismatched InGaAs/InP Epitaxial Layers and Thermophotovoltaic Cells

The results of study of minority carrier lifetime in p-type and n-type InGaAs double heterostructures (DH) and thermophotovoltaic (TPV) cells with InPAs step-graded buffer layers grown on InP substrates are summarized. The active layer carrier concentration was varied in the range from 10¹⁵ to 10¹⁸ cm^-3. The carrier lifetime constants were determined from photoluminescence (PL) transient and frequency responses under low-injection conditions. The rapid decrease of electron lifetime with decrease of excitation was observed in p-type InGaAs DHs and was attributed to capture of electrons on positively-charged deep-donor recombination centers. It was found that Te-doping of the InPAs buffer layers improves the low-injection electron lifetime. Temperature dependences of radiative efficiency and minority carrier lifetime were studied in sets of DHs with different doping level in order to separate the radiative and non-radiative recombination processes