EPR study of X-ray and UV irradiated GeO{sub}2 glasses prepared by the sol-gel method

摘要

X-ray irradiation of sol-gel derived GeO{sub}2 and 5Na{sub}2 O-94Ge{sub}O{sub}2-lEr{sub}2 O{sub}3 glasses generated many EPR signals: GeE' center (g =1.993-1.994, 1.996-1.997, 2.000); four-coordinated germanium electron trapped center (GEC, or Ge(2); g = 1.987-1.988); self-trapped hole center (g = 2.009-2.015); and another weak signals (g = 1.965, 1.971, 1.977, 1.982, 1.983, 2.015, 2.019, 2.021, 2.025, 2.033). UV irradiation yielded GeE' in the GeO{sub}2 glass and GEC as well as GeE' in a 99.5GeO{sub}2-0.5Er{sub}2O{sub}3 glass. A GeO{sub}2 gel and a 0.5Na{sub}2 O-98.5GeO{sub}2-lEr{sub}2O{sub}3 glass, both of which contained residual OH groups and water, were relatively unaffected by irradiation.