Lithium-Doped Radiation-Resistant Silicon Solar Cells

Photovoltaic measurements indicate that lithium in the n-type region of floating-zone silicon p-on-n solar cells interacts with radiation damage induced by 1 MeV electrons or 16.8MeV protons. The centers formed by this interaction do not degrade the minority-carrier lifetime; therefore, these cells are potentially the most radiation-resistant ones available. The interaction involves the motion of lithium; thus, the cell temperature and the radiation rate are important in establishing the amount of degradation which is observed. At room temperature and low rates, the cell output does not degrade. At room temperature and high rates, the cell output degrades but it recovers after irradiation, i.e. the cells are self-healing. The rate which can be used without causing observable decay in the photovoltaic output increases with the cell temperature.