On the origin of carrier loss in Mg-doped N-polar GaN

The neutral (VN-3MgGa)0 complex was found to be the primary compensator in Mg-doped N-polar GaN. The experimental data showed a sharp drop in hole concentration once [Mg] exceeded ∼1019 cm−3. Temperature-dependent Hall measurements, in conjunction with a charge balance model, revealed that the carrier loss was due to a drastic reduction in acceptor concentration (NA), suggesting that a significant fraction of Mg atoms was incorporated in an electrically neutral configuration. A quantitative semi-empirical model based on the grand canonical formalism pointed to the formation of (VN-3MgGa)0 complexes as the primary cause for the observed carrier loss.