Mg doping of GaN layers grown by plasma-assisted molecular-beam epitaxy

GaN:Mg layers grown by plasma-assisted molecular-beam epitaxy at 650 °C are investigated. Secondary-ion-mass-spectroscopy measurements reveal uniform Mg doping profiles with very sharp boundaries. The amount of incorporated Mg atoms changes approximately linearly with incident Mg flux. Hall measurements on p-type GaN:Mg layers show that about 1%–2% of all Mg atoms are ionized at room temperature. The hole mobility depends strongly on the hole concentration, varying from ${\mu }_p\text{=24\hspace{0.05em}}{\mathrm{cm}}^2/\mathrm{V s}$ for ${\text{p=1.8×10}}^{17} {\mathrm{cm}}^{\mathrm{-3}}$ to ${\mu }_p\text{=7.5\hspace{0.05em}}{\mathrm{cm}}^2/\mathrm{V s}$ for ${\text{p=1.4×10}}^{18} {\mathrm{cm}}^{\mathrm{-3}}.$ GaN p–n diodes with molecular-beam-epitaxy-grown p regions are analyzed using current–voltage measurements.