Growth of GaAsBi alloy under alternated bismuth flows by metalorganic vapor phase epitaxy

► A successful method to epitaxy GaAsBi layer on (0 0 1) GaAs substrate is proposed. ► Reflectance signal is found to change significantly during both bismuth flashes and GaAs growth stages. ► Our growth method provides a GaAsBi graded composition layer and not an alternated Bi/GaAs heterostructure.