The effect of dopant density on the radiation resistance of MOCVD InP solar cells

The effect of base dopant concentration (N_a) on the radiation resistance of n⁺p InP solar cells grown by metallorganic chemical vapor deposition (MOCVD) has been measured and analyzed. The highest efficiency measured after 1×10¹⁶ 1-MeV electrons/cm^-2 was 11.6% which is higher than reported for any other single-junction technology after this fluence. The efficiency of the InP cells degraded at approximately the same rate, independent of the base dopant level for 3×10¹⁵<N_a<2×10¹⁷ cm^-3. However, the short-circuit current, J _sc, degraded more in the heavily doped samples while the open-circuit voltage, V_oc, degraded more in the lightly doped samples. These results have been used to model the effect of the structure, especially the basic thickness, on the radiation response of the cell