Increased radiation resistance in lithium-counterdoped silicon solar cells

Abstract
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.