The activity for non-radiative recombination at dislocations on (0001) basal planes was examined in wurtzite ZnO bulk single crystals. In panchromatic cathodoluminescence intensity maps, the dislocations did not exhibit apparent contrast when they were introduced at elevated temperatures of 923-1073K, while the dislocations introduced at low temperatures (below 623K) were observed as dark bands. It was suggested that the dislocations formed complexes involving point defects, via the thermal migration of point defects at elevated temperatures, resulting in the suppression of the recombination activity. The complexes did not influence the existing emission lines in pre-dislocated crystals

Recombination Activity of Dislocations on (0001) Introduced in Wurtzite ZnO at Elevated Temperatures. Ohno, Y., Tokumoto, Y., Yonenaga, I., Fujii, K., Yao, T., Yamamoto, N.: Physica B: Condensed Matter, 2012, 407[15], 2886-8