Ultrathin Non‐van der Waals Magnetic Rhombohedral Cr₂S₃: Space‐Confined Chemical Vapor Deposition Synthesis and Raman Scattering Investigation

Abstract

Two dimensional (2D) magnetic materials display enormous application potential in spintronic fields. However, most of currently reported magnetic materials are van der Waals layered structure that is easy to be isolated via exfoliation method. By contrast, the studies on non-van der Waals ultrathin magnetic materials are rare, largely due to the difficulty in fabrication. Rhombohedral Cr 2 S 3 , an intensively studied antiferromagnetic transition metal chalcogenide with Neel temperature of ≈120 K, has a typical non-van der Waals structure. Restricted by the strong covalent bonding in all the three dimensions of non-van der Waals structure, the synthesis of ultrathin Cr 2 S 3 single crystals is still a challenge that is not achieved yet. Besides, the study on the Raman modes of rhombohedral Cr 2 S 3 is also absent. Herein, by employing space-confined chemical vapor deposition strategy, ultrathin rhombohedral Cr 2 S 3 single crystals with a thickness down to ≈2.5 nm for the first time are successfully grown. Moreover, a systematically investigation is also conducted on the Raman vibrations of ultrathin rhombohedral Cr 2 S 3 . With the aid of angle-resolved polarized Raman technique, the Raman modes of rhombohedral Cr 2 S 3 for the first time based on crystal symmetry and Raman selection rules are rationally assigned.

Space‐confined microwave synthesis of ternary‐layered BiOCl crystals with high‐performance ultraviolet photodetection

“…Solid bismuth chloride (BiCl 3 ) powder was chosen as the precursor, which was readily to react with the moisture in the air to form the intermediate hydrate BiCl 3 ·H 2 O . Two SiO 2 /Si substrates were stacked together directly to create a narrow gap and a small amount of BiCl 3 powder was located in the confined space . Turning on the microwave, the BiCl 3 ·H 2 O was heated by a molecular interaction with the electromagnetic field and then decomposed to square shape bismuth oxychloride flakes on the SiO 2 /Si substrate.…”

2D Re‐Based Transition Metal Chalcogenides: Progress, Challenges, and Opportunities

“…Owing to the simplicity and effectivity, the space-confined CVD growth approach has been widely utilized to controllably synthesize large-area monolayer ReSe 2 film and other 2D TMDs materials. [104][105][106][107] Besides the above works, Zhang's group reported the synthesis of ReSe 2 with high crystal quality on gold foil substrate, which provides the convenience for in-situ studying their electrical properties by using scanning tunneling microscope (STM). [108][109][110][111] Lee and coworkers prepared high uniformity and continuity ReS 2 film on the transparent flexible glasses at a relatively low temperature.…”

Recent Advances in Two-Dimensional Magnets: Physics and Devices towards Spintronic Applications

“…Firstly, it is always promising to enrich the family members of 2DMMs. In general, 2DMMs should not only cover van der Waals crystals but also non-van der Waals ones, such as CrSe, Cr 2 S 3 , and Mn 3 N 2 [83][84][85][86]. On the other hand, to the best of our knowledge, 2DMMs with ferromagnetic or antiferromagnetic order have been reported extensively; however, chiral helimagnetic or topological magnetic order in truly 2D materials is almost unexplored.…”