Surface reconstructions during growth of GaAs1−xBix alloys by molecular beam epitaxy

An in-situ electron diffraction study of surface reconstructions on (001) oriented GaAs1−xBix films has been carried out during growth by molecular beam epitaxy on GaAs substrates in the temperature range from 250°C to 400°C. We observe (1×3), (2×3) and (2×4) reconstructions on both GaAs and GaAs1−xBix surfaces. A (2×1) surface reconstruction is observed in the presence of Bi at low As2:Ga flux ratios. Higher Bi incorporation and stronger photoluminescence were observed for GaAs1−xBix films grown on (2×1) reconstructed surfaces, compared to samples grown on (1×3) surfaces. The location of the various surface phases has been mapped out as a function of temperature, Bi flux and As2:Ga flux ratio.