An EPR study was made of the divacancy in silicon, produced by 1.5-MeV electron irradiation at room temperature, under illumination with polarized light. A light-induced alignment of divacancies among the various Jahn-Teller distortion directions in the lattice is observed for the singly positively charged state, as monitored directly in the corresponding EPR spectrum. Optical bands at 1.8 and 3.9 μ, which have been previously correlated with the positive divacancy, are found to have no alignment effect. Instead a band at ∼ 2.15 μ, not previously reported, is found to have the maximum alignment efficiency. The transition-dipole-moment direction for this band is determined with respect to the defect axes.

• Received 11 January 1972

DOI:https://doi.org/10.1103/PhysRevB.5.3988