Optical and Structural Properties of Emerging Dilute III-V Bismides

In this paper, we present a review of optical and structural studies of GaBixAs1-x epilayers grown by Molecular Beam Epitaxy (MBE) on (311)B and (001) GaAs substrates with different As fluxes. The results indicate that under near-stoichiometric conditions the bismuth incorporation is higher for samples grown on (311) B GaAs substrates than for those grown on (001) GaAs. In addition, carrier localization effects in GaBiAs layers are clearly revealed for both samples by optical measurements. The (311) B samples showed evidence of higher density of defects. It has also been found that the nonradiative centers play a significant role in the recombination process in this material system. The influence of post-growth annealing on the microstructural, optical, and magneto-optical properties was also investigated. An important improvement of optical and spin properties after thermal annealing due to the reduction of defects in the GaBiAs layers was observed.