Mayank Jain, Department of Physics, Technical University of Denmark

A coupled PL/OSL system to understand the dynamics of the metastable states

Metastable states form by charge (electron and hole) capture in defects in solids. These play an important role in dosimetry, information storage, and many medical and industrial applications of photonics. Despite many decades of research, charge transfer across metastable states and its role in luminescence production is poorly understood. This is largely because the measurement of luminescence from metastable states involve several processes such as detrapping, transport, competition, and electron-hole (e-h) recombination.

Here a novel, coupled PL/OSL (photoluminescence / optically stimulated luminescence) system in a natural alumina-silicate (feldspar) is discussed. Infrared PL (IRPL) in feldspar is capable of directly probing the trapped electrons, whereas, OSL results from e-h recombination. A comparison of the two signals leads to new analytical methods that elucidate for the first time detrapping, thermal diffusion and radiation-induced growth of electron and holes. Such results provide unique insights for modelling of localised charge transfer across the metastable states.