Inversion Domain Boundaries in GaN Wires Revealed by Coherent Bragg Imaging

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• 作者：St茅phane Labat ; Marie-Ingrid Richard ; Maxime Dupraz ; Marc Gailhanou ; Guillaume Beutier ; Marc Verdier ; Francesca Mastropietro ; Thomas W. Cornelius ; Tobias U. Sch眉lli ; Jo毛l Eymery ; Olivier Thomas
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：September 22, 2015
• 年：2015
• 卷：9
• 期：9
• 页码：9210-9216
• 全文大小：463K
• ISSN：1936-086X

文摘

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.