ELECTRONIC-STRUCTURES OF P-TYPE GAN CODOPED WITH BE OR MG AS THE ACCEPTORS AND SI OR O AS THE DONOR CODOPANTS

We have investigated the interactions between p-type dopants (Be and M g) and n-type codopants (Si and O) in p-type codoped GaN using first-p rinciples calculations. Our results reveal that the co-incorporation o f Be(Mg)(Ga) with O-N or Si-Ga in codoped p-type GaN produces high Be( Mg) concentrations with stable ionic charge distributions markedly due to a decrease In the Madelung energy in contrast to p-type GaN doped with only Be(Mg). Our calculations thus predict that the ''codoping me thod (doping n- and p-type dopants at the same time)'' is effective fo r the fabrication of high-conductivity p-type GaN with a wurtzite stru cture. (C) 1998 Elsevier Science B.V. All rights reserved.