Radiation resistance and comparative performance of ITO/InP and n/p InP homojunction solar cells

The radiation resistance of ITO/InP cells processed by DC magnetron sputtering is compared to that of standard n/p InP/GaAs homojunction cells. After 10 MeV proton irradiations, it is found that the radiation resistance of the present ITO/InP cell is comparable to that of the n/p homojunction InP cell and that both InP cell types have radiation resistances significantly greater than that of GaAs. The relatively lower radiation resistance observed at higher fluence for the InP cell with the deepest junction depth is attributed to losses in the cell emitter region. Diode parameters obtained from I_sc-V_oc plots, data from surface Raman spectroscopy, and determinations of surface conductivity type are used to investigate the configuration of the ITO/InP cells. It is concluded that these latter cells are n/p homojunctions, the n-region consisting of a disordered layer at the oxide-semiconductor interface.