Open AccessRole of threading dislocations on the growth of HgCdTe epilayers investigated using monochromatic X‐ray Bragg diffraction imaging
Author(s) -
Yildirim Can,
Ballet Philippe,
Santailler Jean-Louis,
Giotta Dominique,
Obrecht Rémy,
Tran Thi Thu Nhi,
Baruchel José,
Brellier Delphine
Publication year - 2021
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s1600577520014149
Subject(s) - materials science , diffraction , molecular beam epitaxy , dislocation , optics , monochromatic color , bragg's law , lattice constant , substrate (aquarium) , epitaxy , diffraction topography , crystallography , x ray crystallography , optoelectronics , chemistry , nanotechnology , physics , oceanography , layer (electronics) , geology , composite material
High‐quality Hg 1– x Cd x Te (MCT) single crystals are essential for two‐dimensional infrared detector arrays. Crystal quality plays an important role on the performance of these devices. Here, the dislocations present at the interface of CdZnTe (CZT) substrates and liquid‐phase epitaxy grown MCT epilayers are investigated using X‐ray Bragg diffraction imaging (XBDI). The diffraction contributions coming from the threading dislocations (TDs) of the CZT substrate and the MCT epilayers are separated using weak‐beam conditions in projection topographs. The results clearly suggest that the lattice parameter of the growing MCT epilayer is, at the growth inception, very close to that of the CZT substrate and gradually departs from the substrate's lattice parameter as the growth advances. Moreover, the relative growth velocity of the MCT epilayer around the TDs is found to be faster by a factor of two to four compared with the matrix. In addition, a fast alternative method to the conventional characterization methods for probing crystals with low dislocation density such as atomic force microscopy and optical interferometry is introduced. A 1.5 mm × 1.5 mm area map of the epilayer defects with sub‐micrometre spatial resolution is generated, using section XBDI, by blocking the diffraction contribution of the substrate and scanning the sample spatially.