Ultraviolet luminescence in AlN

The defect related luminescence in the near UV region between 3 and 4 eV has been investigated in insulating, n-type and irradiation damaged AlN. A single luminescence band around 3.3 eV with a full width at half maximum of more than 500 meV, is attributed to a donor-acceptor pair transition at low temperatures. The substantial linewidth and a Stokes shift of around 1.3 eV result from strong electron-phonon coupling of the deep acceptor. While the chemical nature of the donor remains ambiguous, the acceptor species is attributed to the isolated Al vacancy, i.e. V-Al(3). This luminescence band might be interesting for studying n-type compensation mechanisms in AlN. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim