Synthesis of 2H‐1T′ WS₂‐ReS₂ Heterophase Structures with Atomically Sharp Interface via Hydrogen‐Triggered One‐Pot Growth

Abstract

2D transition metal chalcogenides (TMDs) with different compositions, phase structures, and properties offer giant opportunities for building novel 2D lateral heterostructures. However, the studies to date have been largely limited to homophase TMD heterostructures, while the construction of heterophase TMD heterostructures remains a challenge. Herein, the synthesis of 2H-1T′ WS 2 -ReS 2 heterophase junctions with high-quality interface structure via a hydrogen-triggered one-pot growth approach is reported. Sequential introduction of hydrogen during growth system, which acts as a "switch" to selectively turn off the growth of ReS 2 while turning on the growth of WS 2 , allows WS 2 to seamlessly grow around ReS 2 to form the WS 2 -ReS 2 heterojunction. Moreover, WS 2 prefers to nucleate at the vertices of ReS 2 grain with fixed lattice orientation, which makes the surrounding WS 2 grains merge into single crystal. Scanning transmission electron microscopy reveals high crystal quality of the heterojunction with an atomically sharp 2H-1T′ heterophase interface. Transient absorption spectroscopy indicates that the photocarriers can effectively separate at the heterophase interface. Based on the high quality heterophase junction, prominent rectification characteristics and polarization-dependent photodiode properties are achieved. This study provides a robust way for the controlled synthesis of 2D heterophase structures, which is essential for their fundamental studies and device applications.

Controllable growth of type‐II Dirac semimetal PtTe2 atomic layer on Au substrate for sensitive room temperature terahertz photodetection

“…[25][26][27] For example, large-area, high crystal quality MoS 2 , WS 2 , and ReS 2 with tunable thickness as well as their heterostructures and alloys have been synthesized via CVD growth. [28][29][30][31][32] Notably, only a few works reported the CVD synthesis of 2D PtTe 2 crystals, and several critical issues need to be resolved for satisfying its practical device applications. For instance, utilizing the tellurium-vapor transformation approach, large-scale 2D PtTe 2 layers were obtained from the predeposited Pt film.…”

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

“…Moreover, the polarization-dependent photoresponse was also achieved from ReX 2 -based alloys and heterostructures. [132,152,154] Hence, the robust linear dichroism photodetection with high photoresponsivity reported on the above ReX 2 -based materials demonstrates a route to exploit the intrinsic anisotropy of 2D materials and opens up new ways for the applications of 2D materials for light polarization detection. At this stage, a deeper understanding of the photocurrent and carrier recombination mechanisms is needed for the optimization of photodetector performance.…”

“…Recently, our group developed a hydrogentriggered one-pot growth approach to synthesize 2H-1T′ WS 2 -ReS 2 heterophase junctions with high-quality interface structure (Figure 9d). [154] The sequential introduction of hydrogen during growth system, which acts as a "switch" to selectively turn off the growth of ReS 2 while turning on the growth of WS 2 , allows WS 2 to seamlessly grow around ReS 2 to form the lateral WS 2 -ReS 2 heterojunction. As a result, an atomically sharp 2H-1T′ heterophase interface was obtained and no cross-doping existed in the two phase regions as confirmed by the Raman, PL and STEM characterization.…”

2D Homojunctions for Electronics and Optoelectronics

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erties of the individual components and thus exhibit diverse functions and superior performance in high mobility transistors, nonvolatile memories, and high sensitivity photodetectors. [25][26][27][28][29][30] There are some non-negligible shortcomings in the 2D heterojunctions, such as chemical intermixing, [31] grain boundaries, [32][33][34] lattice mismatch, [35,36] and discontinuous band alignments, [37][38][39] which result in massive carrier scattering and trapping centers at the heterointerfaces, and thus deteriorate the interface charge transfer efficiency and finally affect the overall device performance. On the contrary, 2D homojunctions formed by a single 2D material usually have a high-quality carrier diffusion channel and a continuous band bending, which might be more beneficial for carrier transport and separation at the interface owing to the natural matching of their chemical and electronic structures.

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