The effect of defects, and especially deformation-induced defects, upon the luminescence of bulk single crystals was investigated by means of cathodoluminescence observations in a scanning electron microscope. The crystals were compressed along the <100> direction to plastic strains of 3% or 6.4%. The deformation was found to cause a reduction in the total cathodoluminescence intensity of the sample. The cathodoluminescence images of deformed samples revealed dark slip-bands. The cathodoluminescence spectrum of an undeformed crystal at 85K contained the near-bandedge emission at 2.8eV, and a broad band which peaked at 2.2eV; with a shoulder at about 2eV. Deformation at the lower strain caused only slight spectral changes whereas, in the heavily deformed crystal, a strong relative enhancement of the deep-level band was observed in the range of 2 to 2.2eV.

P.Fernández, J.Piqueras, A.Urbieta, Y.T.Rebane, Y.Shreter: Solid State Phenomena, 1998, 63-64, 207-14. See also: Semiconductor Science and Technology, 1999, 14[5], 430-4