Increased radiation resistance in lithium-counterdoped silicon solar cells

Lithium‐counterdoped n+p silicon solar cells are found to exhibit significantly increased radiation resistance to 1‐MeV electron irradiation when compared to boron‐doped n+p silicon solar cells. In addition to improved radiation resistance, considerable damage recovery by annealing is observed in the counterdoped cells at T≤100 °C. Deep level transient spectroscopy measurements are used to identify the defect whose removal results in the low‐temperature anneal. It is suggested that the increased radiation resistance of the counterdoped cells is primarily due to interaction of the lithium with interstitial oxygen.