Materials Chemistry

Morphology and growth habit of a new flux-grown layered semiconductor KBiS2 revealed by diffraction-contrast tomography

Authors

Abstract

Single crystals of rhombohedral KBiS2 were synthesized for the first time, and the structure, growth habit and properties of this layered semiconductor are presented. The single crystals form from a reactive K2S5 salt flux and are still embedded in the residual flux, without removal from the reaction vessel throughout the whole study. Laboratory diffraction contrast tomography (LabDCT) is used to identify the crystalline phase, orientation, and microstructure of crystals. Meanwhile, powder and single crystal X-ray diffraction were performed to determine detailed crystallographic information. Morphology of the crystalline assemblies observed by absorption contrast tomography reveals screw-dislocation-driven growth to be the dominant mechanism. First-principles electronic structure simulations predict rhombohedral KBiS2 to be a semiconductor with an indirect band gap, which was confirmed by experiment. This study demonstrates how non-destructive tomography imaging and 3D crystallography methods can lead to advances in discovering new materials and studying crystal growth mechanisms.

Content

Thumbnail image of KBiS2.pdf

Supplementary material

Thumbnail image of KBiS2 Supporting Information.pdf
KBiS2 tomography supporting information
(1), Tube-Overview: movie of the whole tube. (2), Crystal-Detail: movie of absorption contrast tomography region, Figure 1(f). (3), Laue: movie of Laue diffraction which no background deduction. (4), Table S1: crystallographic information of rhombohedral KBiS2 from single crystal XRD. (5), Figure S1: powder XRD and structure for both rhombohedral and cubic KBiS2. (6), Figure S2: SEM and microscope pictures of rhombohedral KBiS2 crystals. (7), Figure S3: Laue diffraction rotation tracking with {hkl} planes and crystal orientations. (8), Figure S4: DFT-PBE electronic band structure. (9), Figure S5: HSE06 electronic band structure

Supplementary weblinks

KBiS2 tomography movies
(1), Tube-Overview: movie of the whole tube. (2), Crystal-Detail: movie of absorption contrast tomography region, Figure 1(f). (3), Laue: movie of Laue diffraction which no background deduction.