Published online by Cambridge University Press: 22 February 2011
We observed the coexistence of two types of ordered structures, Cu3Au and CuPt, in Zn0.4Fe0.6Se epilayers grown on ZnSe buffer layers on (001) GaAs substrates by transmission electron microscopy. In addition, the Cu3Au ordered structure exists with a multi-faceted domain shape. Energy dispersive x-ray spectra from these domains showed higher Fe concentration than in the disordered matrix. However, in Zn0.5Fe0.5Se epilayers, we only observed CuAu-I ordered multi-faceted domains. The samples with relatively high Fe concentration (x ≈0.6) also showed domains of FeSe with a hexagonal structure with triangular form coexisting with Cu3Au ordered domains. Strain-induced interdiffusion takes place between the buffer layer and the epilayer as evidenced by a rough interface between the alloy and the buffer layer.