Metalorganic vapour phase epitaxial growth of GaAsBi alloy has been carried out at atmospheric pressure in horizontal geometry reactor. In order to achieve the growth of this alloy, we have investigated the growth conditions which allow epitaxial layers of a good crystalline quality with a maximum bismuth concentration. Growth parameters such as growth temperature, trimethylbismuth (TMBi) flow and V/III ratio were checked on a wide range. Growth temperature was varied between 365 and 450 degrees C, TMBi flow was checked in the range below 2 mu mol/min and V/III ratio was varied between 6 and 20. According to our experimental results based on in-situ reflectivity measurements, scanning electron microscopy observations and high resolution X-ray diffraction analysis, it was found that the maximum Bi concentration reached in GaAs1-xBix layers was 3.7%. This maximum, relative to atmospheric-pressure metalorganic vapour phase epitaxy technique, was found under a growth temperature of 420 degrees C, a TMBi flow of 0.2 mu mol/min and a V/III ratio of 9.5. (C) 2008 Elsevier B.V. All rights reserved.