Electronic properties of $p$-GaN(Mg) irradiated with reactor neutrons

The effect of irradiation with full-spectrum reactor neutrons and predominantly fast reactor neutrons (up to a fluence of 8 $\times$ 10$^{18}$ cm$^{-2}$) on the electrical properties of epitaxial $p$-GaN(Mg) films at different initial doping levels (in the range of hole concentrations $p$ = 10$^{17}$–10$^{19}$ cm$^{-3}$) is analyzed. It is found that neutron irradiation induces an increase in the resistivity of the initial material to 10$^{10}$ $\Omega$ cm at 300 K. It is shown that, at high neutron fluences, the resistivity of the material decreases because of the hopping conduction of charge carriers over radiation defect states. The study of isochronous annealing at 100–1000$^\circ$C reveals stages of donor-defect (100–300$^\circ$C, 500–700$^\circ$C, 750–850$^\circ$C) and acceptor-defect (300–500$^\circ$C, 650–800$^\circ$C) annealing in the neutron-irradiated $p$-GaN(Mg) samples.