Interface structure and chemistry in ZnSe/Ga[sub 1-x]Mn[sub x]As/ZnSe heterostructures.

The structure and chemical composition of ZnSe/Ga[sub 1-x]Mn[sub x]As/ZnSe multilayers grown on (100) GaAs substrates are investigated by high-resolution transmission electron microscopy imaging and spectroscopy techniques. While all layers grow epitaxially and the Ga[sub 1-x]Mn[sub x]As layer is free of planar defects, a high density of stacking faults is observed in the ZnSe layer over Ga[sub 1-x]Mn[sub x]As. The composition of the ferromagnetic layer is measured to be Ga[sub 0.93]Mn[sub 0.07]As, and the Mn valence was determined to be 2[sup +]. Compositional profiles across the interfaces quantified by electron energy-loss spectroscopy show that the ZnSe/Ga[sub 1-x]Mn[sub x]As interfaces are wider than the ZnSe/ GaAs-substrate interface, which is mainly attributed to interfacial roughness. [ABSTRACT FROM AUTHOR]