Optical Study Of Relaxation Dynamics Of Photo-Induced Absorption Of Cr-Doped Bi12sio20 Crystals

The charge carriers tunneling produced in the forbidden band of the Cr doped Bi12SiO20 has been studied using photo-induced absorption (PIA) spectroscopy. These are excited by a green nanosecond neodymium-doped Yttrium Aluminum Garnet; Nd: Y3Al5O12 (ND: YAG) laser at a wavelength of 532 nm. The relaxation dynamics of these charge carriers in this crystal are characterized by a stretched exponential decay with a highly correlated constant of a streched life time ? and a stretched coeffcient ?. The charge transport processes of these charge carriers in the forbidden band in this crystal shows nearly temperature independent behavior from the Arrhenius plot. This corresponds to a very weak dependence of the PIA of the charge carriers? dynamics within the forbidden band. The electo-optical descriptions are explained in the framework of the fast and slow time decays of the charge carriers tunneling within the localized states.