Introducing and studying origin of deep electron traps in Ba1-xZrSi3O9:xEu for optical data storage

Abstract Eu ions doped Ba1-xZrSi3O9:xEu materials are synthesized by solid state reaction method, facing optical data storage applications. The doping of Eu ions introduces deep electron traps at 0.90 eV below the conduction band minimum of Ba1-xZrSi3O9:xEu (1400 °C air). Moreover, the trap distribution is tunable, and there are only deep traps in sample Ba0·85ZrSi3O9:0.15Eu (1400 °C Ar/H2) with the disappearance of shallow traps. Deep traps can prevent information from loss, while the disappearance of shallow traps can eliminate interference to deep traps by avoiding redeployment of electrons between shallow and deep traps over time. Further, post-sintering in a reducing atmosphere after sintering in the air can increase the concentration of deep traps and deepen the color of samples, while post-sintering in the air after sintering in a reducing atmosphere can obviously decrease the concentration of deep traps and the color of samples return to white from yellow. Experimental results indicate that the deep traps in samples Ba1-xZrSi3O9:xEu should originate from oxygen vacancy defects, which also serve as color centers. First principles calculations show that VO1 oxygen vacancy defects introduce obvious defect energy levels below the conduction band minimum of BaZrSi3O9-VO1, which further illustrate the deep traps should originate from VO1 oxygen vacancy defects located at the connection of layer to layer in layered matrix. Ba1-xZrSi3O9:xEu materials with deep electron traps are good candidates for optical data storage.