Intrinsic Restructuring of Defects in Amorphous SiO2 in Manipulating Electron-Trapping Levels via First Principles Study

A model of undefected and defected amorphous SiO2 has been constructed from Rietveld Refinement to investigate the effect of defect structure to its properties. Atomic level study for both structure were carried out using plane-wave pseudo potential by density functional theory. A new electrons trapping energy level appears within the 5.853eV band gap of a-SiO2 for oxygen-excess defected structure. This defect energy level reduces as more number of excess oxygen atoms was added to the structure of a-SiO2. A spectral emission at 388nm from SiO2 glass excited with 350nm (200mW) laser demonstrates the existence of the defective states in the structure in trapping electron at 3.273eV energy level.