Abstract
Abstract Solar energy devices and their applications are among the most important research nowadays. Ternary Ag-In-Se and their related materials, especially the AgInSe2 ternary compound, have very good photo-galvanic properties, and have been intensively investigated. The knowledge of Ag-In-Se phase equilibria and In/Ag2Se interfacial reaction is crucial to the development and preparation of Ag-In-Se solar energy materials. However, very limited literatures are available. This study thus plans to work on the phase equilibria and interfacial reactions. The first part is about phase equilibria. Ternary Ag-In-Se alloys were prepared with pure Ag, In and Se. The alloys were equilibrated at 450oC, and the equilibrium phases were determined. Surprisingly, Ag whisker was found in the Ag-rich alloys after annealing in 450oC, It was also observed that these whiskers’ growth were with preferred growth direction and plane. With XRD and TEM analysis, a preferred orientation is determined. And the Ag whisker formation is a result of stress release from the solidified alloys. The second part is about In/Ag2Se interfacial reactions. The Ag2Se substrate was prepared with pure Ag and Se, and was reacted with pure indium. At the initial stage of reaction in 450oC, a reaction layer was formed at the interface. Two reaction layers were observed after reactions for 3 minutes. The two layers were with different vertical and horizontal morphologies, but were both liquid and In4Se3 phase. In the investigation at 300oC, a reaction layer was observed in initial stage. And the composition was liquid and In4Se3 phase. After 120 minutes reaction, another reaction layer was observed and had a vertical morphology. Composition of this layer was Ag2In and In4Se3 phase. AgInSe2 phase was also observed in this layer.