Growth of high Bi concentration GaAs_1-xBi_x by molecular beam epitaxy, R. B. Lewis, M. Masnadi-Shirazi, T. Tiedje, Appl. Phys. Lett. 101, 082112 (2012)

The incorporation of Bi is investigated in the molecular beam epitaxygrowth of GaAs_1-xBi_x. Bi content increases rapidly as the As₂:Ga flux ratio is lowered to 0.5 and then saturates for lower flux ratios. Growth under Ga and Bi rich conditions shows that Bi content increases strongly with decreasing temperature. A model is proposed where Bi from a wetting layer incorporates through attachment to Ga-terminated surface sites. The weak Ga-Bi bond can be broken thermally, ejecting Bi back into the wetting layer. Highly crystalline films with up to 22% Bi were grown at temperatures as low as 200  C.