Fine core structure and spectral luminescence features of freshly introduced dislocations in Fe-doped GaN

Abstract

Dislocations introduced by Vickers tip microindentation of an a-plane free-standing semi-insulating Fe-doped GaN halide vapor phase epitaxy (HVPE) crystal were investigated by means of cathodoluminescence and scanning transmission electron microscopy techniques. Detailed combined analyses of both spectral properties and the core structure of the introduced a-screw dislocations revealed that Fe-doped GaN exhibit not only dislocation-bound emission at ∼3.35 eV of perfect a-screw dislocations previously found in such kind of samples but also luminescent bands at 3.1–3.2 and 3.3 eV due to dissociated a-screw dislocations and extended dislocation nodes previously observed only in low-resistance n-GaN. For the first time, all these luminescent bands were observed together in the same sample. Structural studies revealed the coexistence of the dislocations with the dissociated and the perfect core as well as with extended dislocation nodes, thus establishing a correlation between previously observed luminescence bands and a fine dislocation core structure.

Influence of Dislocations Move on Photoluminescence of Mn²⁺ Ions with Various Local Surroundings in ZnS Single Crystals in the Process of Plastic Deformation

“…This leads to a change in the electrical [4,5] and optical characteristics [3,[6][7][8] of the materials under study. In particular, the motion of dislocations that occurs during PD [9,10] changes the immediate environment of luminescence centers and affects the mechanisms of excitation energy transfer, which in turn causes a change in the luminescent properties of deformable materials [11][12][13].…”