Effect of Na2O addition to Ag2O-doped phosphate glasses on enhancement of silver particle precipitation by low-energy ion irradiation

The precipitation of Ag particles in xNa2O-yAg2O-zAl2O3-(1-x-y-z)P2O5 glasses was studied. The volume fraction of quantum-size Ag precipitates was enhanced by nitrogen ion irradiation at room temperature. Ion-irradiation-enhanced precipitation was observed up to a distance of 80 nm from the glass surface. In the absence of Na2O (x=0), Ag was selectively sputtered by the nitrogen ion flux. In glasses containing Na2O, irradiation-induced Ag removal could be suppressed and the amount of precipitates increased. The third-order nonlinear optical susceptibility, χ(3), of the irradiated glasses was estimated to range from 5.5 to 8.8 x 10-7 esu. The large susceptibilities are consistent with the large amount of Ag precipitates. The irradiation-induced decomposition of Ag2O and Na2O is one possible precipitant-forming mechanism. (author)