1. 2 New Materials and Concepts for Cells and Modules
Thin Film (TF), Doping, Rare Earth, Annealing, Structural Properties
Summary / Abstract:
It is well known that rare-earth (RE) ions (erbium, terbium, europium, thulium and so on) are a special kind of photoactive centers with narrow emission lines and long emission lifetimes in various semiconductor materials, including ZnO. In the present work, the influence of europium ions (Eu3+) on the physical properties of ZnO films was investigated. Thin films were fabricated on quartz and p-Si (100) substrates by magnetron sputtering method at 25 ºC. The samples have been annealed at temperature from 400 to 600 °C. X-ray measurements were performed to confirm the crystallinity and phase composition of the films. Morphology and chemical composition of the films were studied using scanning electron microscopy and energy dispersive x-ray spectroscopy, respectively. Particularly, the ZnO:Eu films on silicon substrates exhibit large-scale grain size about of ~ 0.1 - 0.3 μm. The optical characteristics of the samples on glass substrates were obtained from the transmission and reflection spectra. Using photoluminescence (PL) and photoluminescence excitation (PLE) methods are found that ZnO:Eu films exhibit bright red emission which may be useful for the additional generation of nonequilibrium charge carriers in the films. The results presented in this work are important to develop energy efficient solid state lighting devices.