Molecular-beam epitaxy of BeTe layers on GaAs substrates

We investigate the MBE growth and structural quality of BeTe layers on GaAs (001) substrates. We show that although BeTe nucleates in a 2D mode at typi cal ZnSe-MBE temperature, the growth conditions of BeTe and ZnSe are only m arginally compatible. We determine the surface reconstruction of BeTe layer s. The: critical thickness for strain relaxation is 120 nm. However. the re laxation rare is very slow and high-quality samples can be obtained above t he critical thickness. which might be a consequence of the large covalency of BeTe compound. (C) 1999 Elsevier Science B.V. All rights reserved.