Status of diffused junction p/sup +/n InP solar cells for space power applications

We have succeeded in fabricating diffused junction p/sup +/n(Cd,S) InP solar cells with measured AM0, 25/spl deg/C open circuit voltage (V/sub oc/) of 890 mV, which, to the best of our knowledge, is higher than previously reported V/sub oc/ values for any InP homojunction solar cells. The experiment-based projected achievable maximum AM0, 25/spl deg/C efficiency of these cells, using LEC grown substrates, is 21.3%. The maximum AM0, 25/spl deg/C efficiency recorded to date on bare cells is, however, only 13.2% due entirely to nonoptimized front grid, antireflection (AR) coating and emitter thickness. This paper summarizes advances in the technology of fabrication of p/sup +/n InP diffused structures and solar cells, undertaken in an effort to increase the cell efficiency. Based on the high radiation resistance and the excellent post-irradiation annealing and recovery demonstrated in the early tests done to date, as well as the projected high efficiency and low-cost high-volume fabricability, these cells show a very good potential for space photovoltaic applications.