Study of molecular-beam epitactic growth of GaAs on (100) Sc <inf>x</inf>E<inf>1-x</inf>As/GaAs

The growth of GaAs on (100)ScxEr1-xAs/GaAs (x=0 and 0.3) by molecular-beam epitaxy has been studied using transmission electron microscopy. The initial stages of the three-dimensional growth of GaAs on lattice-matched Sc0.3Er0.7As have been investigated at different growth temperatures. Besides (100) epitactic GaAs, there are also areas of {111}- and {122}-oriented GaAs observed on ScxEr 1-xAs. The latter has a simple twin relationship with the neighboring (100) GaAs. Areas of {111}-oriented GaAs have been observed only at growth temperatures above 400 °C and with moderate growth rates. The GaAs islands grown at 480 °C are faceted on {110} and {111} low-index planes. These GaAs islands are elongated along 〈011〉 directions. The anisotropy of the island shape is greater at higher growth temperatures. The growth of GaAs on ScxEr1-xAs as islands is considered to be due to chemical rather than strain effects. The morphology of GaAs layers grown on Sc xEr1-xAs is shown to have a strong dependence on the growth conditions. © 1995 American Institute of Physics.