Critical Materials Parameters for the Development of Amorphous Silicon Alloys

Abstract

AbstractThe desired properties of solar cells are discussed, and a relative figure of merit for the comparison of cells fabricated using different technologies is described. The advantages of utilizing amorphous silicon alloys as the active material in solar cells are enumerated. Selected materials properties of these alloys are described and the physics of their electronic structure is discussed in detail. The necessary steps for achieving commercially viable cells based on amorphous silicon alloys are listed, and it is demonstrated how each of them has been achieved using a technology that incorporates fluorine throughout the entire process. The chemical and physical basis for the superiority of fluorinated material is presented in detail. Continuous web large-area high-efficiency multijunction solar cells are in production. Dual band gap multijunction cells have been tested under continuous air mass 1 exposure for over 2000 hours and show essentially no degradation. Some recent results are presented.