ZnSe epilayers were grown on GaAs (100) substrates by atomic layer epitaxy modified from chemicalhyphen;vapor deposition with thicknesses ranging from 600 to 6000 Aring;. Xhyphen;rayhyphen;diffraction and microhyphen;Raman scattering measurements were carried out to study the effects of strain in the ZnSe epilayers with different thicknesses. The increase in full width at halfhyphen;maximum of doublehyphen;crystal xhyphen;ray rocking curves was observed for layers thicker than the critical thickness, which indicates that the crystallinity gets strongly degraded when the layers are grown over the critical thickness. The critical thickness estimated by xhyphen;ray rocking curves is 1500 Aring;, while that obtained by microhyphen;Raman scattering is 1000 Aring;. This difference suggests that the elastic strain depends on the layer depth for ZnSe epilayers around the critical thickness.
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