Synthesis and Characterization of ReS₂ and ReSe₂ Layered Chalcogenide Single Crystals

Abstract

We report the synthesis of high-quality single crystals of ReS2 and ReSe2 transition metal dichalcogenides using a modified Bridgman method that avoids the use of a halogen transport agent. Comprehensive structural characterization using X-ray diffraction and electron microscopy confirm a distorted triclinic 1T′ structure for both crystals and reveal a lack of Bernal stacking in ReS2. Photoluminescence (PL) measurements on ReS2 show a layer-independent bandgap of 1.51 eV, with increased PL intensity from thicker flakes, confirming interlayer coupling to be negligible in this material. For ReSe2, the bandgap is weakly layer-dependent and decreases from 1.31 eV for thin layers to 1.29 eV in thick flakes. Both chalcogenides show feature-rich Raman spectra whose excitation energy dependence was studied. The lower background doping inherent to our crystal growth process results in high field-effect mobility values of 79 and 0.8 cm2/(V s) for ReS2 and ReSe2, respectively, as extracted from FET structures fabricated from exfoliated flakes. Our work shows ReX2 chalcogenides to be promising 2D materials candidates, especially for optoelectronic devices, without the requirement of having monolayer thin flakes to achieve a direct bandgap.

Electronic and Optoelectronic Applications Based on ReS2

“…Optical graph (a) and SEM image (e) of ReS 2 crystals prepared by the modified Bridgman method. Reproduced with permission . Copyright 2016, American Chemical Society.…”

“…Reproduced with permission. [53] Copyright 2016, American Chemical Society. (b) Schematic depiction for the growth of monolayer ReS 2 by CVD method.…”

Advent of 2D Rhenium Disulfide (ReS2): Fundamentals to Applications

“…This does not involve the use of any transport agent. [23] However, the resulting method makes use of an elevated temperature arrays. [24,36] Unit cell parameters are shown in Table 1.…”

“…BP, ReS2, ReSe2, TiS3, ZrS3) with in-plane structural anisotropy. [7,8,22,23] These benchmark properties make ReS2 a unique material among the TMDs.…”

Rhenium Diselenide Anchored on Reduced Graphene Oxide as Anode with Cyclic Stability for Potassium‐Ion Battery

“…These XPS results were consistent with some previously reported studies. [19,28,33] To characterize the potassium-storage performance of the ReSe 2 @rGO composite, a series of electrochemical tests were performed on a potassium-ion half-cell (PIB) with ReSe 2 @rGO as the anode. Figure 4a shows the cyclic voltammetry (CV) curves of the ReSe 2 @rGO anode in PIB for the first two cycles with a sweep rate of 0.2 mV s À1 in a voltage range between 0.01 and 3 V. As shown during the initial discharge process, two reduction peaks appeared at 1.1 and 0.5 V. The peak located at 1.1 V might be attributed to the insertion of K þ into the interatomic layers of ReSe 2 to form K x ReSe 2 .…”