Abstract
ZnO is an attractive material especially in UV light emitting devices because of its wide band gap and high exciton binding energy. ZnO has also a potential as a host semiconductor for phosphor. In this study, we fabricated non-doped and rare-earth metal doped ZnO epitaxial thin films with/without AlN buffer layer on (0001)sapphire substrates by reactive rf magnetron sputtering. Epitaxial films with very smooth surface were grown at 600C. Photoluminescence(PL) spectra obtained from ZnO films at a suitable sputtering condition, showed dominant band-edge UV emission with little green luminescence. Very strong exiton emission was observed at low temperature less than 70K. The films annealed at 800C in the air showed higher UV intensity than the as-deposited ones although the visible emission was also increased at room temperature. Eu doped ZnO exhibited emissions from Eu at about 615nm and 623nm. We also report the effects of another doping elements.
