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

Intersection Nodes of Basal Screw Dislocations as Luminous Quantum Dots in GaN

“…The spectrum of the single straight a‐screw dislocation (red‐dotted line in Figure (b)) contained a set of additional intense narrow lines at around 3.1–3.2 eV: the main doublet of DRL accompanied with LO‐phonon replicas as it was reported earlier . The integrated intensity of DRL lines was at least two times higher than FE's intensity in dislocation free region under the same excitation conditions.…”

“…As we proposed previously the additional red shift of 0.15 eV of DRL in low‐ohmic GaN with respect to SI GaN is due to the fact that QW level of SF ribbon lies deeper than the level formed by the dislocation‐related CB bending. Accordingly, the energy of the optical transition between SF level and the level of the dislocation‐related VB bending is lower than that between the two intrinsic dislocation‐related levels.…”

“…Commercial GaN crystals contain usually a high density of grown‐in dislocations which act detrimentally on the efficiency of LEDs being the centers of non‐radiative recombination. In contrast to that, freshly introduced screw dislocations was found recently to generate luminescence bands with peak energies at low temperatures of 3.35 eV in iron‐doped semi‐insulating (SI) sample and of 3.15–3.18 eV in specially undoped low‐ohmic n‐GaN. In both kinds of the samples cathodoluminescence (CL) images revealed that the sources of the DRL were straight segments of basal screw dislocations, while the dislocations with the edge component exhibited enhanced non‐radiative recombination only.…”

“…In contrast to that, freshly introduced screw dislocations was found recently to generate luminescence bands with peak energies at low temperatures of 3.35 eV in iron‐doped semi‐insulating (SI) sample and of 3.15–3.18 eV in specially undoped low‐ohmic n‐GaN. In both kinds of the samples cathodoluminescence (CL) images revealed that the sources of the DRL were straight segments of basal screw dislocations, while the dislocations with the edge component exhibited enhanced non‐radiative recombination only. DRL in SI sample vanishes at the temperatures above 100 K while DRL in low‐ohmic GaN samples was shown to persist at room temperature making it, thus, as a possible candidate for 1D UV light source creation.…”

Core properties and mobility of the basal screw dislocation in wurtzite GaN: a density functional theory study

“…They have found them to give rise to a strong luminescence at 3.35 eV. Subsequently, by using scanning electron microscopy in the cathodoluminescence mode, Medvedev et al have shown that a-type screw dislocations luminesce in the spectral range of 3.1-3.2 eV at 70 K [20].…”