An arbitrary number of dislocations were freshly introduced in wurtzite ZnO bulk single crystals by plastic deformation at 923 to 1123K, and the optical properties were examined by photoluminescence spectroscopy. ZnO, including a high density (more than 109/cm2) of dislocations, showed excitonic light emission with photon energies of 3.100 and 3.345eV, as well as their LO-phonon replicas, at a temperature of 11K, and the intensities increased with increasing dislocation density.

Light Emission Due to Dislocations in Wurtzite ZnO Bulk Single Crystals Freshly Introduced by Plastic Deformation. Ohno, Y., Koizumi, H., Taishi, T., Yonenaga, I., Fujii, K., Goto, H., Yao, T.: Applied Physics Letters, 2008, 92[1], 011922