Journal of Applied Physics (2019)
Links between bismuth incorporation and surface reconstruction during GaAsBi growth probed by in situ measurements
Bismuth incorporation and surface reconstruction have been studied simultaneously during GaAsBi growth by molecular beam epitaxy by means of in situ wafer curvature monitoring and reflection high energy electron diffraction, respectively. Growth temperature and flux ratio have been varied successively. As/Ga atomic ratio close to unity has been applied for the study of the growth temperature effect. During the growth regime under the (1 × 3) reconstruction, Bi incorporation is found to be independent of the growth temperature, for temperatures where Bi desorption is insignificant. On the contrary, Bi incorporation becomes highly dependent on the growth temperature as soon as the (2 × 1) reconstruction regime is reached. Only for the lowest temperatures, the Bi incorporation reaches the same level during the (2 × 1) reconstruction than for the (1 × 3) reconstruction. When the As/Ga flux ratio is increased, the bismuth incorporation is observed to decrease for GaAsBi growth in the (2 × 1) reconstruction regime. Our results indicate that the (1 × 3) and (2 × 1) surface reconstructions are always successively observed and that an energy barrier has to overcome to transit from the (1 × 3) to the (2 × 1) reconstruction, with this mechanism being temperature dependent. Finally, a difference in surface stress with reconstruction has been identified.