Abstract
ZnO and ZnO:Al whiskers were epitaxially deposited using an atmospheric chemical-vapor-deposition reactor on the c-cut sapphire substrate. Luminescence properties of the undoped and Al doped ZnO whiskers were investigated by a method of cathodoluminescence. An intensive cathodoluminescence emission band peaked at 385 nm was observed on the sample of the undoped ZnO whiskers. The origin of this emission is discussed in terms of free exciton recombination. The Al incorporation in ZnO whiskers leads to the total quenching of the free exciton emission, giving rise to the appearance of blue emission peaked at ∼420 nm instead of the band at 385 nm. The blue emission was found to be conversely dependent on the concentration, which is discussed in term of concentration quenching process.
