Talk abstract

Aluminum nitride is a wide band-gap (6.2 eV) material having a wurtzite structure. Oxygen is a well-known natural dopant for this material [1]. Oxygen ions can substitute the nitrogen or form some more complicated structures of defects in the crystalline lattice. The energy levels of oxygen-related defects are usually situated inside the band-gap and their spectral characteristics fall into the spectral region of ultraviolet (UV), visible (V) or near infrared (IR) light. The present work is aimed with a study of some natural defect structure in AlN. Complex investigation of spectral characteristics was performed. The spectra of luminescence and its photoexcitation, luminescence kinetics as well as photostimulated luminescence (PSL) of photorecharged defects were studied. The AlN ceramics sintered at different conditions were used. A structure of a complex oxygen-related defect consisting of the oxygen ions and an aluminium vacancy is proposed [2,3]. This defect complex is responsible for the UV-blue luminescence, which is predominant in the UV-V spectral region caused by the recombination-tunneling mechanism. Investigation of other defects responsible for 600 nm and 1000 nm luminescence bands of AlN are in progress.

[1] R.A.Youngmann and J.R.Harris. J. Am. Ceram. Soc., 73 (1990) 3238. [2] S.Schweizer, U.Rogulis, J.M.Spaeth, L.Trinkler and B.Berzina. Phys. Stat. Solidi (b), 219 (2000) 171. [3] B.Berzina, L.Trinkler, J.Sils and E.Palcevskis. "Oxygen-related defects and energy accumulation in AlN ceramics". Rad. Eff. and Deff. in Solids, (2001) (in press).