Deep-level defects in homoepitaxial p-type GaN

The author has investigated deep-level defects in homoepitaxial layers of p-type GaN with Mg doping concentrations of similar to 1.4 x 10(17) cm(-3) grown by metal-organic chemical vapor deposition on GaN substrates. Five deep-level defects were revealed with their optical onsets at similar to 1.80, similar to 2.48, and similar to 3.18 eV above the valence band and at similar to 3.08 and similar to 3.28 eV below the conduction band. The similar to 1.80, similar to 3.18, and similar to 3.28 eV levels had high defect concentrations. In particular, the density of the similar to 1.80 and similar to 3.28 eV levels increased with decreasing depth, probably due to segregation of Mg toward the surface. These three deep-level defects are most likely associated with Ga vacancies, N vacancy-related compensating donors, and deep Mg acceptors, respectively. Published by the AVS.