Regensburg 2019 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 35: HL Poster II
HL 35.4: Poster
Wednesday, April 3, 2019, 17:30–20:00, Poster E
Electron Beam Induced Current (EBIC) Investigations of Freshly Introduced a-screw Dislocations in GaN — •Tobias Westphal and Michael Seibt — University of Göttingen, IV. Physical Institute, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
Even though GaN is already a widely used semiconductor, the effect of defects on the properties of GaN is not fully understood yet. As GaN has a quite high grown-in dislocation density, in the order of 106 cm−2 - 108 cm−2 depending on the growth technique, investigating the electrical properties of dislocations is of particular interest.
In previous work it was shown that indentation perpendicular to the basal (0001) plane in specially undoped low-resistance GaN creates a-screw dislocations. Those freshly introduced dislocations are showing dislocation related luminescences (DRL) with an energy peak at around 3.18 eV. This red shift of about 300 meV with respect to the band gap can not be explained by a perfect dislocation. However a dissociated dislocation, where the stacking fault ribbon forms a quantum well, would be a possible explanation. Therefore, structural investigations of the dislocation core with high spatial resolution are of tremendous interest.
The freshly introduced dislocations as well as the grown-in dislocations are investigated with EBIC to make recombination centres visible. Under electron beam irradiation recombination enhanced dislocation glide (REDG) occurs, making high resolution TEM (HRTEM) challenging. Hence, EBIC studies of REDG are performed in order to prepare for HRTEM measurements.