Investigation of bulk and surface minority carrier lifetimes in metamorphic InAsSb grown on GaAs and Si

Monolithic integration of III-V-based optoelectronic devices onto Si wafers provides enormous benefits to many device manufacturing technologies. Therefore, it is essential to understand the effect of limiting factors such as dislocations on the material properties. In this paper, we study the minority carrier lifetimes in mid-wave infrared InAsSb alloys grown on lattice-matched GaSb and lattice-mismatched semi-insulating GaAs and Ge/Si substrates. Time-resolved microwave reflection measurement has been performed to study the carrier dynamics and different recombination mechanisms over the temperature range of 20-300K at various optical injection levels. The sample on GaAs is found to have a lower lifetime over the entire temperature region than the sample on the Ge/Si substrate. The threading dislocation density values estimated from the lifetime analysis were found to be 2.9 +/- 0.2 times larger in the sample on GaAs when averaged over the temperature range of 70-200K. Furthermore, we studied the contribution of various recombination mechanisms, and it was shown that the lifetime in the sample on GaAs is dominated by the Shockley-Read-Hall recombination up to 140K, above which the Auger recombination is the limiting factor. This transition temperature is 80K and 100K for the samples on GaSb and Ge/Si, respectively. We have also investigated the effect of the surface recombination on the total lifetime. The extracted bulk lifetime was found to be up to 2 x higher when the surface effect was excluded.

Automated summary

This paper investigates the monolithic integration of III-V-based optoelectronic devices on Si wafers, focusing on the effect of limiting factors such as dislocations on material properties, and the influence of different substrates on the material performance. The experimental results show variations in carrier lifetimes and recombination mechanisms of the sample under different temperature ranges and optical injection levels. The threading dislocation density in the GaAs sample is significantly higher than that in the Ge/Si substrate sample, and there are distinct differences in recombination mechanisms.