Electron irradiation effects on the shunt resistance of silicon solar cells

Shunt resistance R_sh values greater than 5×10⁶ μ have been measured for high efficiency silicon solar cells fabricated by a low temperature diffusion technique, whereas lower values ((0.5-1.0)×10⁵ μ) were obtained for ion-implanted solar cells. A degradation in R_sh values by an order of magnitude was observed after electron irradiations of 1 MeV to a fluence of 1 × 10¹⁶ e^- cm^-2. Temperature dependence studies indicated a rapid decrease in R_sh above a threshold temperature which is sensitive to the device quality. As the fluence of irradiation increased, very little shift in the threshold temperature towards lower values was observed. The degradation in R_sh causes an enhancement in the dark saturation current which is partly responsible for degradation in the open-circuit voltage of the devices.