The Controllable Synthesis of High‐Quality Two‐Dimensional Iron Sulfide with Specific Phases

Abstract

2D Fe‐chalcogenides have drawn significant attention due to their unique structural phases and distinct properties in exploring magnetism and superconductivity. However, it remains a significant challenge to synthesize 2D Fe‐chalcogenides with specific phases in a controllable manner since Fe‐chalcogenides have multiple phases. Herein, a molecular sieve‐assisted strategy is reported for synthesizing ultrathin 2D iron sulfide on substrates via the chemical vapor deposition method. Using a molecular sieve and tuning growth temperatures to control the partial pressures of precursor concentrations, hexagonal FeS, tetragonal FeS, and non‐stoichiometric Fe7S8 nanoflakes can be precisely synthesized. The 2D h‐FeS, t‐FeS, and Fe7S8 have high conductivities of 5.4 × 105 S m−1, 5.8 × 105 S m−1, and 1.9 × 106 S m−1. 2D tetragonal FeS shows a superconducting transition at 4 K. The spin reorientation at ≈30 K on the non‐stoichiometric Fe7S8 nanoflakes with ferrimagnetism up to room temperature has also been observed. The controllable synthesis of various phases of 2D iron sulfide may provide a route for synthesizing other 2D compounds with various phases.

Vacancy-plane-mediated exfoliation of sub-monolayer 2D pyrrhotite

“…Two-dimensional pyrrhotite has been produced by several methods, such as a hydrothermal method, 8–10 systematic reduction of pyrite FeS 2 films by vacuum annealing, 11 and a molecular sieve-assisted CVD method. 12 In 2017, Chen et al obtained pyrrhotite nanosheets in a top-down approach from a pyrrhotite–hexylamine intermediate (inorganic–organic hybrid intermediate) synthesized by the hydrothermal method through ultrasonic treatment in an organic solvent. 13 However, these bottom-up methods produce stable stoichiometries without ordered vacancy planes and only yield 2D layers with thicknesses that are limited by the unit cell dimension.…”

In situ topotactic formation of an inorganic intergrowth bulk NiS/FeS@MgFe-LDH heterojunction to simulate CODH for the photocatalytic reduction of CO2

“…When NiMgFe-MMO was vulcanized, FeS (PDF#37-0477) and NiS (PDF#12-0041), which were also in the hexagonal crystal system, appeared, as evidenced by the XRD correlation diffraction peaks and Raman activity signals. [35][36][37] At the same time as obtaining MgFe-CO 3 2− -LDHs, the diffraction peaks of layered structure in XRD (Fig. 1A), CO 3 2− vibrational peaks in FTIR (Fig.…”

Synthesis of air-stable 1T-CrS2 thin films and their application in high-performance floating-gate memory

“…Chemical vapor deposition (CVD) is recognized as a premier technique for producing high-quality 2D materials. [30][31][32][33][34] Yet, fabricating large-scale, uniformly thin layers of 1T phase CrS 2 presents significant challenges, including issues with small sizes and excessive thickness. [35][36][37] Addressing this, there's a critical need for innovative approaches capable of consistently producing expansive, thin layers of 1T-CrS 2 .…”