Composition control of CdSeTe layers grown by molecular beam epitaxy

CdSeTe layers were grown on GaAs(1 0 0) substrates by molecular beam epitaxy. The beam-intensity ratios of Se to Te atoms were changed to control the composition of the CdSeTe mixed crystals. The Te atoms were more readily incorporated into the epilayers than the Se atoms under the competition for incorporation of Se and Te atoms. he J(VI)/J(II) beam-intensity ratio dependence of the Se composition was studied. The Se composition increased with decrease in J(VI)/J(II) ratio. At a J(VI)/J(II) ratio of 0.05 the beam-intensity ratio of Se to Se+Te coincided with the Se composition. This result indicates that the Se and Te atoms are incorporated without competition on the Cd stabilized surface. We considered the behavior of physisorbed atoms and the heat of formation of the compounds and discussed the situation of the growing surface of the CdSeTe epilayers, comparing it with the reported results of ZnSeTe epilayers. (C) 2002 Elsevier Science B.V. All rights reserved.