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Abstract Strain modulation is a crucial way in engineering nanoscale materials. It is even more important for single photon emitters in layered materials, where strain can trap a delocalized exciton, leading to quantum emission. Herein, we apply strain by using the piezoelectric relaxor ferroelectric substrate. In addition to the strain-tuning of energy and polarization, we report on new observations, including the enhanced polarizability and tunable diamagnetic shift, from the charged localized excitons. As indicated from the polarization-resolved measurements, we attribute the formation of charged localized excitons to selenium vacancy defects. The shallow defect trap, supported by the value of g-factor, further allows for strain-modulation of the electron-hole overlap, hence resulting in the tunable diamagnetic shift. Our results provide a new perspective in integrating layered materials with functional substrates. The contrasting features observed from the charged localized excitons also signify the prospect of charged localized emitters for quantum science and technology. 

Abstract One-dimensional (1D) van der Waals (vdW) nanowires, formed from molecular chains bonded through weak interactions, represent a significant departure from traditional nanowires by offering the potential to miniaturize functional devices to the molecular scale while maintaining crystallinity, a feature attributable to their exfoliable nature and chemically inert surfaces. However, the lack of efficient synthesis methods has hindered the exploration of their intrinsic properties and potential applications. The production of vdW nanowires has predominantly relied on the exfoliation of bulk crystals, leaving their direct synthesis largely unexplored. In this work, we introduce a novel solid-state growth technique that facilitates the high-yield and scalable fabrication of single-crystal Ta2Ni3Se8 (TNS) nanowires, achieving a consistent thickness of 100 nm and lengths extending to several millimeters. We further demonstrate a few centimeter scale alignments of as-grown nanowires and show that these nanowires can be easily dry exfoliated to produce several nanometer-thick, air-stable nanowires. Employing density functional theory, we investigate the bonding characteristics within these nanowires, identifying a highly anisotropic bonding density that significantly contributes to their facile exfoliation. Moreover, the development of Schottky device arrays on individual TNS nanowires and subsequent electrical transport measurements affirm the uniform Schottky contact properties along their entire length, characterized by a barrier height of approximately 0.39 eV. The successful synthesis of structurally and electronically uniform, ultralong TNS nanowires may open a new avenue in developing integrated molecular electronics and sensors using 1D vdW materials. 

AbstractClick to copy section link One-dimensional (1D) ternary transition metal chalcogenides (M2X3Y8) have emerged as a promising class of materials for advanced electronic and optoelectronic applications. This Mini-Review comprehensively explores recent advancements in their synthesis, characterization, and integration into functional devices. The studied nanowires display exceptional performance as semiconductor 1D nanostructures in photodetection, field-effect transistors, and gas sensing. Their unique 1D structure, tunable electronic properties, and high stability make them attractive candidates for future research and development in the field of materials science. 

Immediately after the demonstration of the high-quality electronic properties in various two dimensional (2D) van der Waals (vdW) crystals fabricated with mechanical exfoliation, many methods have been reported to explore and control large scale fabrications. Comparing with recent advancements in fabricating 2D atomic layered crystals, large scale production of one dimensional (1D) nanowires with thickness approaching molecular or atomic level still remains stagnant. Here, we demonstrate the high yield production of a 1D vdW material, semiconducting Ta2Pd3Se8 nanowires, by means of liquid-phase exfoliation. The thinnest nanowire we have readily achieved is around 1 nm, corresponding to a bundle of one or two molecular ribbons. Transmission electron microscopy (TEM) and transport measurements reveal the as-fabricated Ta2Pd3Se8 nanowires exhibit unexpected high crystallinity and chemical stability. Our low-frequency Raman spectroscopy reveals clear evidence of the existing of weak inter-ribbon bindings. The fabricated nanowire transistors exhibit high switching performance and promising applications for photodetectors.