Temperature Dependence of Damage Coefficient in Electron Irradiated Solar Cells

Measurements of light-generated current versus cell temperature on electron-irradiated n/p silicon solar cells show the temperature coefficient of this current to increase with increasing fluence for both 10¿-cm and 2¿-cm cells. A relationship between minority-carrier diffusion length and light-generated current was derived by combining measurements of these two parameters: 1) versus fluence at room temperature, and 2) versus cell temperature in cells irradiated to a fluence of 1 × 1015e/cm2. This relationship was used, together with the light-generated current data, to calculate the temperature dependence of the diffusion-length damage coefficient. The results show a strong decrease in the damage coefficient with increasing temperature in the range experienced by solar panels in synchronous earth orbit; i.e., 200 to 330°K, and a significant temperature dependence of the ratio of the damage coefficient for 2¿-cm cells to that for 10¿-cm cells.