Effects of oxygen incorporation in p-type AlN crystals doped with carbon species

We investigate the electronic structures of n-type O-doped and p-type C-dop ed AlN crystals with wurtzite structures based on ab initio electronic band -structure calculations. We find the strongly localized impurity states for p-type C-doped AIN compared with that for n-type O-doped AIN. For the mate rials design to fabricate high-conductive p-type C-doped AlN, we study the effects of oxygen incorporation on p-type C-doped AIN. We verify the deloca lization of the impurity states for p-type AIN:(2C and O) with a decrease i n the Madelung energy. (C) 1999 Elsevier Science B.V. All rights reserved.