Structural Flexibility and Alloying in Ultrathin Transition-Metal Chalcogenide Nanowires

Abstract

Metallic transition-metal chalcogenide (TMC) nanowires are an important building block for 2D electronics that may be fabricated within semiconducting transition-metal dichalcogenide (TMDC) monolayers. Tuning the geometric structure and electronic properties of such nanowires is a promising way to pattern diverse functional channels for wiring multiple units inside a 2D electronic circuit. However, few experimental investigations have been reported exploring the structural and compositional tunability of these nanowires, due to difficulties in manipulating the structure and chemical composition of an individual nanowire. Here, using a combination of scanning transmission electron microscopy (STEM) and density functional theory (DFT), we report that TMC nanowires have substantial intrinsic structural flexibility and their chemical composition can be manipulated. Rotational twisting, axial kinking, and branching of an individual nanowire is consistently observed and junctions with well-ordered atomic structures can be fabricated. We also show that the density of states of these nanowires can be finely tuned via alloying either the chalcogen or the transition-metal elements, where the chalcogen alloying can be further controlled by the acceleration voltage of the electron beam during the fabrication. The results open up the possibility of tailoring the properties of TMC nanowires, paving the way for robust ultrasmall interconnects in TMDC-based 2D flexible nanoelectronics.

Optoelectronic and photonic devices based on transition metal dichalcogenides

“…Large-area growth of TMDCs has been looked at for wafer-scale fabrication processes [65]. Alloyed compounds based on TMDCs have also been studied for improved optical device performance [66][67][68][69][70]. Many reports have studied various charge transfer mechanisms and carrier dynamics to understand and exploit the rich physics of TMDC materials [71][72][73][74][75][76].…”

Novel Pd2Se3 Two-Dimensional Phase Driven by Interlayer Fusion in Layered PdSeLin1, Zuluaga2, Yu3 et al. 2017Phys. Rev. Lett.Self Cite1174600View full textAdd to dashboardCite

“…Chalcogen deficiency in layered TMD materials can be intentionally introduced by electron irradiation and often induces massive reconstructions leading to new metastable structures [25][26][27][28]. We attempted to create Se-deficient conditions using electron irradiation in PdSe 2 , i.e., artificially providing a reconstruction condition for Pd 2 Se 3 in the PdSe 2 matrix through interlayer fusion and simultaneously captured the in situ dynamical growing process.…”

<italic>In-situ</italic> study of electron irradiation on two-dimensional layered materials

“…MoS纳米线(图7(c)), 并通过原位电学测量实验论证了 纳米线的电学性质. 他们还发现这种电子束辐照的技 术路径同样适用于MoSe, WS, WSe等其他过渡金属硫 化物纳米线的可控加工 [43] , 也适用于复杂准一维纳米 结构体系的构筑(图7(d))和MoS x Se 1x , Mo x W 1x S等准 一维合金体系的加工 [46] . 此外, 如前文所述, MoS 2 中S原子比Mo原子更容 易发生离位, 因此Mo原子容易在纳米孔边缘富集及 重构 [5] .…”

“…(d) Sequential images of the nucleation of the inversion domain, scale bars are 0.5 nm [43] 2.4 其他二维材料 除上述二维材料外, 基于透射电子显微镜的电 子辐照现象研究还可以延展到其他二维材料体系. 例如, Kaiser课题组 [49] 和Novoselov课题组 [50] 分别利 列, 标尺为 1 nm [5] ; (b) Mo 5 S 4 纳米带的原子结构模型及基于该模型的TEM模拟图像 [5] ; (c) MX纳米线的原子结构模型 [43] ; (d) 通过控制电子束辐 照的区域可以实现复杂一维结构体系的构筑, 标尺为 0.5 nm [46] [5] . (b) Atomic model of Mo 5 S 4 nanoribbon [5] .…”

“…(c) Atomic structural model of MX nanowires [43] . (d) Structural flexibility of MoSe nanowires, scale bars are 0.5 nm [46] 3 结语与展望…”