Structural and electrical transport studies of reduced in hydrogen surface of bismuth germanate glass

Bismuth nanoclusters embedded in germanate glass matrices and surface layer of bismuth grains have been obtained by thermal treatment in hydrogen atmosphere of Bi0.33Ge0.67O1.83 glass. Confirmed by AFM and XRD measurements a simple model of two conducting layers is proposed. The influence of time and temperature of reduction on the properties of the reduced samples have been studied. A change in surface conductivity caused by melting of Bi granules has been observed in all studied samples. The possibility of existence of a superconducting state in reduced bismuth germanate glasses has been discussed.