Observation of surfactant properties of thallium in the epitaxial growth of indium arsenide on gallium arsenide

Because of the large lattice mismatch between InAs and GaAs, the growth of the former on the (001) surface of the latter undergoes a well-known transition from a layer-by-layer mode to an island mode at an equivalent coverage of 1-2 monolayers (ML). We have observed a suppression of this transition when growth proceeds under a simultaneous thallium flux. The thallium is not significantly incorporated into the InAs layer; however, approximately I ML may remain at the interface. The effect of the thallium on the electronic properties of the InAs is investigated.