Extended defects acting as non-radiative recombination center or those acting as radiative one were, respectively, studied by transmission electron microscopy under the illumination of a monochromatic light or cathodoluminescence spectroscopy combined with light illumination. By means of this method, defect levels associated with dislocations in ZnO, which were introduced at above 923K, were determined. It was proposed that (i) a screw dislocation, presumably acting as non-radiative recombination center, glides under the illumination of a light with photon energy above 2.48 to 2.61eV, due to an electron-hole recombination at a defect level of 2.48 to 2.61eV depth, and (ii) a mixed dislocation acts as radiative recombination center with a defect level of 3.1eV depth.

In situ Analysis of Optoelectronic Properties of Dislocations in ZnO in TEM Observations. Ohno, Y., Taishi, T., Yonenaga, I.: Physica Status Solidi A, 2009, 206[8], 1904-11