Recombination parameters in antimonide-based materials using RF photoreflectance

Antimonide-based materials are promising candidates for thermophotovoltaic (TPV) cells, infrared lasers and photodetectors. Minority carrier lifetime is a critical parameter which determines the performance of these devices. Radio-Frequency (RF) photoreflectance measurements and one-dimensional device simulations have been used to determine bulk and surface recombination parameters in epitaxially grown 0.50 to 0.60 eV InGaAsSb.; The RF photoreflectance technique senses changes in sample conductivity as carriers recombine following excitation by a laser pulse. A one-dimensional device simulation tool is used to model the sheet conductance transient response to above bandgap optical excitation. When sample decay times are extracted from the RF photoreflectance measurements, the recombination parameters can be obtained by matching the transient decay times from the simulations with the measured decay times.; Measurements and analysis on 2 × 1017 cm −3 doped 0.55 eV p-InGaAsSb active layers with variable capping layers give SRVs of ∼680 cm/s for 2 × 1017 cm −3 doped AlGaAsSb capping layers, ∼1350 cm/s for 2 × 1018 cm−3 p-GaSb capping layers, and ∼5000 cm/s for undoped GaSb capping layers. The 2 × 1017 cm −3 doped samples have a low-level bulk lifetime of 80 to 100 ns. A higher bandgap and higher doping concentration in the capping layer are most effective in reducing SRV.; Radiative and Auger coefficients compatible with the measured decay time of a sample can be obtained after removing the contribution of Shockley-Read-Hall (SRH) and surface lifetimes from the measured decay time. The experimental decay times observed with 2 × 1017 cm−3 doped samples during the low-level injection region of the decay transients are compatible with an Auger coefficient (C) ∼1 × 10 −28 cm6/s and a radiative coefficient (B) ∼3 × 10−11 cm3/s.; The Auger and radiative recombination coefficients obtained from high-level injection decay times show very good agreement with values obtained from low-level injection conditions. Combining the uncertainties in parameter extraction for the various samples evaluated, a radiative recombination coefficient (B) of 3 ± 1.5 × 10−11 cm3/s and Auger coefficient (C) of 1 ± 0.5 × 10−28 cm6/s is obtained for 0.55 eV InGaAsSb lattice matched to GaSb.