Surface ionic conductivity, lattice disorder, and space charge region in thin silver bromide layers

Carefully controlled conditions of evaporation allow the preparation of epitaxial layers of pure AgBr. The temperature dependence of the conductivity of layers with varying thickness is measured. This in principle makes possible the splitting of the conductance into surface and bulk components. The bulk conductivity of the layers is found to be practically identical with that of pure large single crystals of AgBr, which until now has not been observed. For the first time considerable surface conductance is directly observed not only for {111} but for {200} layers too. All parameters characterizing the Frenkel disorder in the subsurface region are evaluated from 150 °C down to room temperature.