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 inverted perpendicular C to 400 degrees C. We observe (1 x 3), (2 x 3) and (2 x 4) reconstructions on both GaAs andGaAs(1-x)Bi(x) surfaces. A (2 x 1) surface reconstruction is observed in the presence of Bi at low As-2:Ga flux ratios. Higher Bi incorporation and stronger photoluminescence were observed for GaAs1-xBix films grown on (2 x 1) reconstructed surfaces, compared to samples grown on (1 x 3) surfaces. The location of the various surface phases has been mapped out as a function of temperature, Bi flux and As-2:Ga flux ratio. (C) 2011 Elsevier B.V. All rights reserved.