On the Origin of Carrier Loss in Mg-Doped N-Polar GaN

Abstract

The neutral $(V_N-3Mg_{Ga})^0$ 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 ~$10^{19} cm^{-3}$. 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 ($N_A$), suggesting that a significant fraction of Mg atoms incorporated in an electrically neutral configuration. A quantitative semi-empirical model based on the grand canonical formalism pointed to the formation of $(V_N-3Mg_{Ga})^0$ complexes as the primary cause for the observed carrier loss.