Photoluminescence, conductivity and structural study of terbium doped ZnO films grown on different substrates

摘要

The effect of substrate material (Si, SiO2, Al2O3) on structural, optical and electrical properties of terbium doped ZnO films (Tb-ZnO) has been investigated by the X-ray diffraction, Raman scattering, atomic force microscopy, photoluminescence and infrared reflection methods. All films consist of micron size clusters of closely packed ZnO grains separated by deep trenches. The width of the trenches depends on the substrate material, being the largest in the Tb-ZnO/Al2O3 one. It is shown that the film on Al2O3 substrate contains the largest amount of extended and point defects. This film also demonstrates the highest intensity of Tb3+ -related photo-luminescence, while the film on Si substrate shows the lowest. On the contrary, the largest free carrier concentration evaluated from the infrared reflection spectra is found for Tb-ZnO/Si film and the lowest one is for the Tb-ZnO/Al2O3 film.