Impact of free charged carrier concentration on the atomic core structure and electronic properties of dislocations in gallium nitride

• Applicant: Professor Dr. Michael Seibt
• Subject Area: Experimental Condensed Matter Physics ; Synthesis and Properties of Functional Materials
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 323634749

The starting point of this project which is a cooperation of the Petersburg State University and the Georg-August-Universität Göttingen, is the hypothesis the capture of free electrons to electron states of the stacking fault ribbon quantum well at dislocations affects their core structure and, in turn, electronic properties of dislocations in GaN. For the first time we plan to investigate systematically the dependence of the atomic core structure of dislocations introduced by plastic deformation in GaN crystals on their conductivity type and free carrier concentration. DRL and electrical levels will be monitored on the same samples which allows to establish correlations between dislocation core structure and electronic properties. As a further important aspect, the impact of electron excitation on the motion dislocations will be analyzed and quantified. A major implication of this Fermi-level-dependent atomic core structure and spectral position of DRL would be the possibility to electronically switch the core structure by external means, e.g. by the external voltage applied to the space charge region of a Schottky diode. Accordingly, one may expect that the DRL spectral response should change in some ranges (now between 3.15 eV and 3.35 eV) for dislocations situated at a certain depth in Schottky diode. This assumption is intended be checked in this project. A perspective goal of the project is to open the route to the production of extremely high efficient light emitting diodes based on DRL. The state-of-the art wafer bonding technology in the combination with SmartCut technique allows to produce industrially regular networks of screw dislocation on the sample depth of hundreds of nanometers. Such LEDs based on DRL in silicon bonded wafers have been already produced.

• DFG Programme: Research Grants
• International Connection: Russia
• Cooperation Partner: Professor Dr. Oleg Vyvenko