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Title: Synthesis and in situ high pressure Raman spectroscopy study of AlN dendritic crystal

Graphical abstract: - Highlights: • The sample is the typical dendritic crystal structure. • The phase transition of AlN dendritic crystal is researched. • The Raman signal of rock salt AlN is observed under high pressure. • Grüneisen parameters and phase transition criterion are discussed. - Abstract: AlN dendritic crystal was synthesized by the direct current arc discharge apparatus. X-ray diffraction (XRD) patterns indicated that the sample is hexagonal AlN and preferentially grown along the a-axis direction. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) images reveal that the product mainly consists of micron AlN dendritic crystal. In situ high pressure Raman spectra of AlN dendritic crystal has been measured in the pressure ranged from ambient pressure to 32.97 GPa at room temperature by using diamond anvil cell. According to the Raman scattering results, the phase transition from the wurtzite to rock salt was found at about 20.73 GPa by the appearance of a new Raman signal. Above 20.73 GPa, a new Raman signal due to disorder-activated Raman scattering in the rock salt phase was observed. In addition, the pressure coefficients, phase transition criterion, and mode Grüneisen parameters of AlN dendritic crystal, which could be different from that ofmore » other AlN, are carefully discussed.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [1] ;  [2] ; ; ; ;  [1] ;  [2]
  1. Institute of Condensed State Physics, Jilin Normal University, Siping 136000 (China)
  2. (China)
  3. School of Science, Shenyang Ligong University, Shenyang 110159 (China)
Publication Date:
OSTI Identifier:
22341774
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 48; Journal Issue: 9; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ALUMINIUM NITRIDES; CRYSTAL STRUCTURE; DENDRITES; PHASE TRANSFORMATIONS; PRESSURE COEFFICIENT; RAMAN EFFECT; RAMAN SPECTRA; RAMAN SPECTROSCOPY; SALT DEPOSITS; SCANNING ELECTRON MICROSCOPY; SYNTHESIS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION