title: Inversion Domain Boundaries in GaN Wires Revealed by Coherent Bragg Imaging.
abstract: Interfaces between polarity domains in nitride semiconductors, the so-called Inversion Domain Boundaries (IDB), have been widely described, both theoretically and experimentally, as perfect interfaces (without dislocations and vacancies). Although ideal planar IDBs are well documented, the understanding of their configurations and interactions inside crystals relies on perfect-interface assumptions. Here, we report on the microscopic configuration of IDBs inside n-doped gallium nitride wires revealed by coherent X-ray Bragg imaging. Complex IDB configurations are evidenced with 6 nm resolution and the absolute polarity of each domain is unambiguously identified. Picoscale displacements along and across the wire are directly extracted from several Bragg reflections using phase retrieval algorithms, revealing rigid relative displacements of the domains and the absence of microscopic strain away from the IDBs. More generally, this method offers an accurate inner view of the displacements and strain of interacting defects inside small crystals that may alter optoelectronic properties of semiconductor devices.
authors: IM2NP UMR 7334 , Aix Marseille Université, CNRS, Université de Toulon, F-13397 Marseille, France.
authors: Stéphane
authors: S
authors: Labat
authors: IM2NP UMR 7334 , Aix Marseille Université, CNRS, Université de Toulon, F-13397 Marseille, France.|ID01 ESRF , F-38043 Grenoble, France.
authors: Marie-Ingrid
authors: MI
authors: Richard
authors: Université Grenoble Alpes, SIMAP , F-38000 Grenoble, France.|CNRS, SIMAP , F-38000 Grenoble, France.
authors: Maxime
authors: M
authors: Dupraz
authors: IM2NP UMR 7334 , Aix Marseille Université, CNRS, Université de Toulon, F-13397 Marseille, France.
authors: Marc
authors: M
authors: Gailhanou
authors: Université Grenoble Alpes, SIMAP , F-38000 Grenoble, France.|CNRS, SIMAP , F-38000 Grenoble, France.
authors: Guillaume
authors: G
authors: Beutier
authors: Université Grenoble Alpes, SIMAP , F-38000 Grenoble, France.|CNRS, SIMAP , F-38000 Grenoble, France.
authors: Marc
authors: M
authors: Verdier
authors: IM2NP UMR 7334 , Aix Marseille Université, CNRS, Université de Toulon, F-13397 Marseille, France.
authors: Francesca
authors: F
authors: Mastropietro
authors: IM2NP UMR 7334 , Aix Marseille Université, CNRS, Université de Toulon, F-13397 Marseille, France.
authors: Thomas W
authors: TW
authors: Cornelius
authors: ID01 ESRF , F-38043 Grenoble, France.
authors: Tobias U
authors: TU
authors: Schülli
authors: Université Grenoble Alpes , F-38000 Grenoble, France.|"Nanophysique et Semiconducteurs" Group, CEA, INAC-SP2M , F-38000 Grenoble, France.
authors: Joël
authors: J
authors: Eymery
authors: IM2NP UMR 7334 , Aix Marseille Université, CNRS, Université de Toulon, F-13397 Marseille, France.
authors: Olivier
authors: O
authors: Thomas
keywords: GaN wires; coherent X-ray Bragg imaging; displacement field; inversion domain boundary