Influence of Pulling Rates on the Thermoluminescence and Optically Stimulated Luminescence of α-Al2O3:C Crystals Grown by the Edge-Defined, Film-Fed Growth Technique

Abstract

In this work, α-Al2O3:C crystals were grown by the edge-defined, film-fed growth method with different pulling rates. The influence of pulling rate on the optical, thermoluminescence (TL), and optically stimulated luminescence (OSL) properties of the as-grown α-Al2O3:C crystals was investigated. All the α-Al2O3:C crystals grown with different pulling rates show a single TL glow peak and an invariable blue emission band at 415 nm. With an increasing pulling rate in the 0.1–0.7 mm/min range, the absorption coefficient of optical absorption bands at 206 and 256 nm increased, the TL and OSL dose response improved, the TL peak shifted to higher temperatures, and the OSL decay rate increased. When the pulling rate is increased to 1 mm/min, the absorption coefficients of the bands at 206 and 256 nm, the TL temperature and intensity, the OSL intensity, and the decay rate declined. The TL and OSL dose response of the as-grown α-Al2O3:C crystals shows a linear–sublinear saturation characteristic. The pulling rates almost show no influence on the crystals' saturation dose. The α-Al2O3:C crystal grown with the pulling rate of 0.7 mm/min shows the best TL and OSL properties.