Quasi-One-Dimensional Molybdenum Disulfide Nanoribbons

One-dimensional (1D) materials, such as nanowires, nanotubes, and nanorods, have been studied intensively recently due to their unusual structural characteristics and novel physical properties^1–3. Similarly, 1D structures of transition metal dichalcogenides (TMDs), such as WS₂ nanorods, have been shown to exhibit striking functionalities compared to their two-dimensional (2D) counterparts, such as enhanced photovoltaic effect in bulk, in the absence of a p-n junction [1]. These findings can lead to many exciting opportunities for their utilization in optoelectronic devices, such as solar cells, photodetectors, laser diodes, and light-emitting diodes.<br/><br/>This paper will discuss a novel approach for synthesizing MoS₂ nanostructures with tunable dimensionality ranging from 2D to 1D. In our process, epitaxial precursors of transition metal oxides, i.e., ultra-thin films of MoO_x (x&lt;3) grown by Pulsed Laser Deposition (PLD), serve as precursors [2,3]. We will show that the addition of halides during sulfurization leads to unidirectional growth into quasi-1D MoS₂ nanoribbons. The morphological and atomic resolution imaging studies reveal an anisotropic growth of epitaxial quasi-1D nanoribbons in either 2H or 3H stacking orientation. Tip-enhanced photoluminescence (TEPL) spectroscopy reveals a photoluminescence (PL) emission from the edge of the nanoribbons and no emission from the core of the quasi-1D structures. Moreover, we observe an edge-enhanced secondary harmonic generation (SHG) of the quasi-1D MoS₂ nanoribbons, which will be discussed in detail during the talk. Finally, we will report the first ultrasensitive photodetector based on a single 1D MoS₂ nanoribbon. The highly crystalline quasi-1D ribbon device exhibits a high photocurrent response under illumination and outstanding stability. Photocurrent measurements of single-ribbon photodetector made on SiO₂/Si substrate exhibit a photoresponsivity above 500 AW^-1 at a wavelength of 532 nm, which exceeds that of graphene, MoS₂, or other nanoribbon-based devices. The experimental results show that single-crystalline quasi-1D MoS2 nanoribbons have immense potential for high-performance photodetector applications.<br/><br/><br/><b>References</b><br/>1. Y. J. Zhang, T. Ideue, M. Onga, F. Qin, R. Suzuki, A. Zak, R. Tenne, J. H. Smet, and Y. Iwasa, Nature <b>570</b>, 349 (2019).<br/>2. D. I. Miakota, R. R. Unocic, F. Bertoldo, G. Ghimire, S. Engberg, D. Geohegan, K. S. Thygesen, and <b>S.</b> <b>Canulescu,</b> Nanoscale <b>14</b>, 9485 (2022).<br/>3. F. Bertoldo, R. R. Unocic, Y.-C. Lin, X. Sang, A. A. Puretzky, Y. Yu, D. Miakota, C. M. Rouleau, J. Schou, K. S. Thygesen, D. B. Geohegan, and <b>S. Canulescu</b>, ACS Nano <b>15</b>, 2858 (2021).