Strong morphological dependence of luminescence efficiency and emission wavelength in hexagonal GaN crystallites directly imaged by scanning cathodoluminescence microscopy

On the luminescence of freshly introduced a-screw dislocations in low-resistance GaN

“…At the same time, the involvement of point defects in the formation of the observed DL band cannot be completely ruled out. For example, in [19], it was shown that a DL band close in spectral position to that detected in the present study disappeared after annealing at 500°C; at the same time, a similar luminescence band desig nated in the review [20] as Y 7 was observed by many researchers [21][22][23][24] in undeformed samples and was attributed to point defects near grown in a disloca tions. Theoretical calculations of the energy position of the electronic states of dislocations themselves predict the existence of two groups of such states: shallow delocalized states of the deformation potential and deep states concentrated directly in the core.…”

Microscopic spatial distribution of bound excitons in high-quality ZnO

“…Here we find a gathering of nonradiative recombination centers, which are most likely caused by screw dislocations or bundles of them running in c-direction in the center of hexagonal columns. In fact, the presence of dislocations in the center of hexagonal structures has already been observed in comparable GaN samples [10][11][12].…”

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

“…We have also demonstrated that we can produce both n-type and p-type porous GaN by this methodology with high density of charge carriers (∼10 18 cm -3 ) and even forming low resistivity Ohmic contacts with high work function metals such as Au or Pt [9].…”

“…However, the spectrum recorded in the high intensity region, corresponding to a GaN micron-size particle grown on the porous layer, has a much lower DAP intensity emission relative to the NBE emission, compared to the spectrum recorded in the low intensity region of the porous layer. This effect is likely related to a different Mg doping incorporation of the GaN porous layer and GaN micron-size particles [17] or to a different crystallographic orientation of the two regions [18], which also can be responsible for changes in the incorporation of the Mg impurities.…”