Low-energy electron-beam irradiation and yellow luminescence in activated Mg-doped GaN

Abstract

The effect of low-energy electron-beam irradiation (LEEBI) on native defects and residual impurities in metalorganic-vapor-phase-epitaxy-grown, lightly Mg-doped, p-type GaN was studied by temperature-resolved and excitation power density-resolved cathodoluminescence spectroscopy. Following the LEEBI treatment, the ubiquitous shallow donor–acceptor-pair emission at 3.27 eV decreased, while a deeper DAP emission at ∼3.1 eV dramatically increased in intensity, and a broad yellow luminescence band centered at 2.2 eV evolved. The results clearly indicate that the centers involved in the 3.27 eV transition are not stable during irradiation by low-energy electrons. Further, we report that the LEEBI-treatment not only dissociates neutral Mg-H complexes as intended, but simultaneously dissociates other hydrogenated defect complexes, giving rise to additional radiative recombination channels.

Formation and dissociation of hydrogen-related defect centers in Mg-doped GaN

“…These experiments were undertaken for a range of electron beam powers from E b =2.5 keV and I b =0.14 nA to E b =30 keV and I b =0.36 nA (not shown) and a gradual blueshift of the deeper emission line was observed, which saturated at 3.14 eV. This behaviour is characteristic for a DAP transition and represents a confirmation of other recent results [19]. Similar experiments were carried out for moderately Mg-doped (p-type) GaN annealed in H 2 /N 2 -atmosphere (Fig.…”

Fabrication of p-type porous GaN on silicon and epitaxial GaN

“…The marked intensity variation in band-edge and YL as a function of temperature is seen on a linear scale in the inset. Most probably, the YL arises from a transition between the conduction band or shallow donors 27 and deep acceptor levels caused by crystallographic point defects in the GaN crystals 28 since we find that the YL emission profile and temperature-dependence is similar and characteristic of both undoped and p-type GaN crystals comprising the porous GaN layer. The YL is weakly temperature-dependent and is not found to vary considerably due to Mg incorporation into the lattice.…”

Fully Porous GaN p–n Junction Diodes Fabricated by Chemical Vapor Deposition

“…YL is also present in Mg-doped p-type porous GaN and can arise from a transition between the conduction band or shallow donors [20]. The YL has weak temperature dependence and is not found to vary considerably due to Mg incorporation into the lattice when compared to the undoped sample.…”