Study of ZnO crystals and Zn1−xMxO (M=Co, Mn) epilayers grown by pulsed laser deposition on ZnO(00.1¯) substrate

Crystal defects in Seeded Chemical Vapour Transport (SCVT) and hydrothermal ZnO substrates were characterised mainly by X-ray topography and diffraction. Zn1−xMxO (M=Co, Mn) epilayers were grown on hydrothermal ZnO(00.1¯) substrate by Pulsed Laser Deposition (PLD). It is shown that the epitaxy strains are partially relaxed through dislocations in the {10.0} glide planes. The crystal perfection of the epilayers was analysed by high-resolution X-ray diffraction. Almost intrinsic rocking curves were observed for Zn1−xCoxO epilayers and the c-axis parameter increases proportionally with the Co content. This suggests that Co atoms are well located at substitutional sites in the ZnO matrix. A larger distortion of the ZnO matrix is induced by the insertion of Mn atoms. A paramagnetic behaviour was observed in Zn1−xCoxO epilayers with a low proportion of active Co atoms. A weak ferromagnetic behaviour was observed only for Zn1−xCoxO epilayers when a few Al atoms (1.6%) were incorporated.