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Quantitative order‐parameter measurement in lattice‐mismatched AlInP using precession electron diffraction
Author(s) -
Pasala Xavier,
Pokharel Nikhil,
Ahrenkiel Phil,
Alberi Kirstin,
Forghani Kamran,
Stender Chris
Publication year - 2021
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/jmi.13047
Subject(s) - diffraction , electron diffraction , lattice constant , precession , electron , lattice (music) , reflection high energy electron diffraction , materials science , valence electron , gas electron diffraction , molecular physics , physics , condensed matter physics , crystallography , atomic physics , chemistry , optics , quantum mechanics , acoustics
Abstract Precession electron diffraction (PED) was used to measure the long‐range order parameter in lattice‐mismatched AlInP epitaxial films under investigation for solid‐state‐lighting applications. Both double‐ and single‐variant films grown at 620, 650 and 680 °C were analysed in TEM cross‐section. PED patterns were acquired in selected‐area‐diffraction mode through external microscope control using serial acquisition, which allows inline image processing. The integrated peak intensities from experimental patterns were fit using dynamical simulations of diffraction from the ordered domain structures. Included in the structure‐factor calculations were mean atomic displacements of the anions (P) due to ordering, which were found by valence‐force‐field calculations to have a nearly linear dependence on order parameter. A maximum order parameter of S = 0.36 was measured for a double‐variant specimen grown at 650 °C.