The recombination mechanism of Mg-doped GaN nanorods grown by plasma-assisted molecular-beam epitaxy

Magnesium-doped GaN nanorods were grown on Si(111) substrates by plasma-assisted molecular-beam epitaxy. Time-integrated and time-resolved photoluminescence measurements were carried out to study the optical transitions. Two emission lines corresponding to blue emission at about 3.26 and 3.18 eV, with their corresponding phonon replicas, were observed. These peaks are attributed to conduction band to shallow acceptor transitions and to defects associated with column/substrate interface–shallow Mg acceptor complexes, respectively.