Thermally stimulated luminescence in aluminium nitride crystals

Abstract

Abstract Electronic levels of point defects in aluminium nitride (AlN) bulk single crystals are evaluated using thermally stimulated luminescence (TSL). As the crystals were grown using AlN source material of different purity levels, the samples show different concentrations of silicon, oxygen, carbon, and (presumably) vacancies and vacancy complexes. In the TSL spectra, broad peaks are detected around 40–70 K, 100 K, 170 K, 220 K, 260 K, and 390 K. The corresponding activation energies were calculated using the Hoogenstraaten method to 8–35 meV, 40–70 meV, 150–215 meV, 130–180 meV, 150–190 meV, 80–170 meV, and 590–770 meV, respectively. TSL peak intensities are discussed in terms of chemical analysis of the samples. The results indicate that oxygen and silicon act as dominant electron traps in AlN. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)