Single-crystalline rocksalt CdO layers grown on GaAs(001) substrates by metalorganic molecular-beam epitaxy

In this letter, we report the growth of single-crystalline rocksalt CdO lay ers on (001) GaAs substrates using ZnS buffer layers. The growth processes of CdO layers were studied by reflection high-energy electron diffraction ( RHEED), and the grown CdO layers were evaluated with atomic force microscop y (AFM), and x-ray diffraction (XRD) measurements. After an initial growth delay, the formation of polycrystalline CdO was observed in RHEED measureme nts during the initial growth of very thin CdO layers. With the increase of the CdO layer thicknesses, streaky RHEED patterns were observed, which ind icate the formation of single-crystalline cubic-phase CdO layers. Surface m orphology of the CdO layers observed by AFM was atomically flat with root-m ean-square roughness of similar to1 nm. The crystalline structures were elu cidated from XRD measurements by the determination of the lattice constant to be 4.686 +/-0.001 Angstrom, indicating the single-phase rocksalt CdO str ucture. (C) 2001 American Institute of Physics.