Summary of Workshop on InP: Status and Prospects

The primary objective of most of the programs in InP solar cells is the development of the most radiation hard solar cell technology. In the workshop, it was generally agreed that the goal is a cell which displays high radiation tolerance in a radiation environment equivalent to a 1 MeV electron fluence of about 10(exp 16)/sq cm. Furthermore, it is desired that the radiation response of the cell be essentially flat out to this fluence - i.e. that the power output of the cell not decrease from its beginning of life (BOL) value in this radiation environment. It was also agreed in the workshop that the manufacturability of InP solar cells needs to be improved. In particular, since InP wafers are relatively dense and brittle, alternative substrates need to be developed. Research on hetero-epitaxial InP cells grown on Si, Ge, and GaAs substrates is currently underway. The ultimate goal is to develop hetero-epitaxial InP solar cells using a cheap, strong, and lightweight substrate.