Basic Research Needs and Opportunities at the Solid-State Interface: Diffusion

An attempt is made to identify the basic research needs and opportunities which exist with respect to S-S interfaces and diffusion in materials and devices relevant to solar energy. Firstly, the generic problems characteristic of solar energy materials are considered. Secondly, the specific problems involving S-S interfaces and diffusion which are peculiar to solar energy materials are described and discussed. Thirdly, the research needs and opportunities associated with these phenomena are identified. General areas of research considered to be "crucial", "important" or "useful" include the following: (1) the development of microstructure; (2) the microstructural stability; (3) the dependence of diffusion and nucleation of new structures on external influences (especially thermal cycling, electric fields and radiation fields); (4) the acquisition of standard reference data (S-S interface diffusion and electrical data); (5) the relationship between microstructure (and its time dependence) and electrical, optical and mechanical properties of composite materials. Finally, priorities are assigned to a number of research areas falling within the above categories.