The effects of post-deposition annealing conditions on structure and created defects in Zn0.90Co0.10O thin films deposited on Si(100) substrate

We analyze the effect of post-deposition annealing conditions on both the structure and the created defects in Zn0.90Co0.10O thin films deposited on the Si (100) substrates by RF magnetron sputtering technique using home-made targets. We concentrated on understanding the homogeneity of substituted Co+2 ions and the annealing effects on the amount of defects in the ZnO lattice. Orientations of thin films are found to be in the [0002] direction with a surface roughness changing from 67±2 nm to 25.8±0.6 nm by annealing. The Co+2 ion substitutions, changing from 7.5±0.3 % to 8.8±0.3 %, cause to form Zn–O–Co bonds instead of Zn–O–Zn and split the Co2p energy level to Co2p1/2 and Co2p3/2 with 15.67±0.06 eV energy difference. In addition, the defects in the lattice were revealed from the correlations between Zn–O–Co bonds and intensity of Raman peak at around 691 cm-1. Furthermore, the asymmetry changes of O1s peak positions in X-ray Photoelectron Spectra (XPS) were also found to be in accordance with the Raman results.