Temperature dependence of the electrical characteristics and radiation damage in MOCVD grown n+p InP solar cells

I-V curve measurements of high efficiency InP solar cells that were illuminated in a deep level transient spectrometer (DLTS) cryostat which allowed precise control of the cell temperature from 90 to 400 K are discussed. A set of temperature variation coefficients for the photovoltaic parameters consistent over all the cells and a clear characterization of the damage induced in the cells by proton irradiation are described. The radiation induced defects were first measured by DLTS on the actual solar cells, and then I- V measurements were done at 90 K. It is shown that, at this low temperature, the I-V measurement did not induce injection annealing. The measurements were repeated following forward bias injection annealing of the solar cell. The results show the actual DLTS spectrum corresponding to the changes in the solar cell performance