Structure And Photoluminescence Properties Of Fe-ZnO Films Deposited On Si And Al₂O₃

ZnO films, a directly wide band gap semiconductor, have been actively studied because of its potential applications. It can be used in solar cells, piezoelectric device, optoelectric device, transparent conducting electrodes and gas sensors. The characteristics of ZnO films can be modulated by the appropriate dopant. Specially, the studies for ZnO based diluted magnetic semiconductors have now attracted much attention of many researchers. To research the effects of Fe dopant on the structure and optical properties of ZnO films, in this paper, we prepared Fe-doped ZnO films by radio frequency (RF) magnetron sputtering and studied the characteristics and optical properties.1. FexZn1-xO(x=0, 0.08 and 0.15) films were deposited on oriented p-type Si (111) substrates by reactive rf magnetron sputtering. XPS and XRD results indicate that Fe2+ ions have substituted for Zn2+ successfully, and the films were well oriented to the c axis (002). The PL peak at 378 nm has a tendency of redshift and the intensity at 414 nm enhances slightly as the Fe concentration increases. The redshift of the peak at 378 nm is usually caused by new detects and band structure deformation resulting from lattice deformation, and the enhancement of the peak at 414 nm may be associated with the interface traps existing in the depletion regions between the ZnO-ZnO grain boundaries which is becoming more and more complicated.2. FexZn1-xO (x = 0, 0.05 and 0.14) films were prepared and annealed in vacuum at 600℃, and their structure and optical properties were studied by XRD, XPS, SEM, PL methods. Fe element appeared in the films as Fe3+ ions which substituted Zn2+ ions sites. And all the films were well oriented to c axis (002). The PL peak at 408nm (arise from exciton recombination) decreased with Fe doped. For the PL peak at 557nm (may arise from oxygen vacancy) increased as the Fe-doping going. And at last, the PL peak at 585nm, as The experimental result indicated, was probably related to local state transition arise from Fe.