Recombination in Low-Bandgap InGaAs

Abstract

We review our investigation of recombination in InxGa1-xAs with indium concentrations ranging between x = 0.53 (i.e., lattice-matched to InP) and x = 0.78. External radiative efficiency measurements were used to study how defect-related and Auger mechanisms compete with radiative recombination. The results indicated that deep mid-gap levels facilitate defect-related recombination in lattice-matched InGaAs while shallower levels play a more important role in the indium-rich alloys. Subsequent subbandgap photoluminescence measurements confirmed the presence of deep levels in the lattice-matched InGaAs. The superlinear excitation dependence of the sub-gap emission led to a defect-related deep-donor/shallowacceptor pair model. Recent cathodoluminescence measurements of the subgap transitions show no spatial contrast, supporting the assignment of this mechanism to evenly distributed point defects. We hypothesize that the deep states observed in lattice-matched InGaAs are related to imperfections in the incorporation of indium or gallium, which become less likely as the indium concentration is increased.

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“…In addition, the effect of Auger recombination was considered to be negligible as the radiative mode of recombination significantly dominates Auger recombination. 46 − 48 …”

“…To maintain congruence with the previous investigations , on the subject and experimental data, a reactive recombination coefficient of 2.3 × 10 –9 cm 3 /s was considered in the bulk of perovskites. In addition, the effect of Auger recombination was considered to be negligible as the radiative mode of recombination significantly dominates Auger recombination. − …”