Formation and behavior of surface layers on electron emission glasses

Changes in alkali-silicate glasses induced with electron irradiation

“…As soon as the surface relaxation is saturated the electric field assisted migration of potassium ions to bulk becomes dominant and therefore concentration decrease is observed. The results obtained from NKS glass strongly support both the role of the surface relaxation in which potassium ions take part and the formation of the potassium rich topmost layer [11]. The potassium concentration in the topmost layer (obtained for low-angle detection) increased more than six times for the small doses while the concentration in the thicker layer (obtained for the normal-angle detection) is significantly lower.…”

“…Brow [10] has shown the formation of metallic sodium on the surface of irradiated binary sodium-silicate glass, whereas no metallic sodium was found in a CaO-containing glass. Using the top-surface sensitive ion scattering spectroscopy (ISS), Then and Pantano [11] observed alkali signal increase at the beginning of electron irradiation and then confirmed to-the-surface migration during the initial stages of electron irradiation.…”

Positron-annihilation monitoring of reduction processes in conducting glasses

“…In the inner layer a more defected structure, resembling SiO x [10], while in the outer -a more compact (S rises but remain lower than in SiO x ), metal-enriched composition is observed. For example, Then and Pantano [1] observed a silicon rich zone in the outer 20-50 nm layer of the surface layer. Other techniques, more element-specific than S-parameter measurements, must be applied for understanding differences between the two layers observed in our present and previous [2] measurements.…”

“…Bismuth-and lead-doped silicon and germanium-oxide glasses are used, among other applications, for electron continuous-dynode multipliers [1]. To make them conducting, reduction procedures in hydrogen atmosphere are applied.…”

Structure and electric conductivity of reduced lead–germanate, bismuth–germanate and bismuth–silicate glasses modified with potassium

“…An improvement of the secondary electron emission coefficient and mechanical properties of the investigated glasses with potassium modification is also expected [9].…”