Direct observation of atom movement in photoexcited ionic-electronic conductors

Abstract

An analysis of the topological, optical, and chemical characteristics of pattern-photoexposed ionic-electronic conductor ${\mathrm{Ag}}_{2}$Se surfaces has revealed a very interesting phenomenon: the formation of hills 100--500 \AA{} in height on the exposed ${\mathrm{Ag}}_{2}$Se/Ge-Se surface area. The hills are a result of pressure caused by the production of Ag metal clusters at the photoexposed ${\mathrm{Ag}}_{2}$Se surface, which results in a four-layer structure of (Ag metal)/ ${\mathrm{Ag}}_{2}$Se/(Ag-doped Ge-Se)/Ge-Se. The Ag hill formation plays a more dominant role in Ag lateral diffusion than Ag photodoping does.