MEASUREMENTS OF THE ELECTRICAL MOBILITY OF SILVER OVER A HOT TIN OXIDE SURFACE

We report on measurements of the drift mobility of silver ions on the surface of tin oxide maintained at temperatures between 400 and 500-de grees-C, in air. Silver contacts are placed on the surface arranged as an inner circular anode and an outer concentric-ring cathode, and by measuring silver advancement outward, mobility can be determined. Meas urements were made as a function of temperature, field intensity, surf ace roughness, and oxygen content of air. Drift-mobility values varied from 10(-8) to 10(-5) cm2/V s. It seems from our results that the dyn amic formation of surface oxide (silver oxide is unstable above 300-de grees-C) is important in understanding silver migration.