Data from: Electrical properties of MoS2 nanotubes

The demand for ultra-low-power, high-performance computing devices continues to drive the advancement of electronic technologies. Among emerging materials, molybdenum disulfide (MoS2) has attracted significant attention due to its favorable electronic and quantum properties, particularly when transitioning from bulk to two-dimensional structures. While MoS2 monolayers have been extensively studied, the electrical behavior of MoS2 nanotubes remains largely unexplored.

In this work, MoS2 nanotubes in cylindrical and collapsed shapes synthesized via chemical vapor transport are investigated, revealing low defect densities and a continuous chiral interface. The surface morphology of collapsed nanotubes is found to be non-uniform and wrinkled, where elevated regions exhibit higher conductivity than depressed areas. In contrast, the highly curved edges display pronounced conductivity variations, ranging from insulating to highly conductive behavior, suggesting localized electron confinement.

Charge injections are shown to significantly modify the surface potential of the nanotubes. Due to the strong anisotropy between in-plane and out-of-plane conductivity in MoS2, injected charge carriers predominantly propagate laterally. However, this transport is influenced by structural imperfections such as defects, edge terminations, and interfacial strain. Additionally, overlapping nanotubes and surface flakes alter local electronic properties through mechanisms including charge trapping, electrostatic gating, and strain-induced scattering.

Furthermore, charge injections induce reversible geometrical changes in cylindrical and in collapsed nanotubes. These deformations, observed as helical twisting along the nanotube axis and gradual plastic deformation, are attributed to a rotational component of the inverse piezoelectric effect inherent to chiral structures. The magnitude of this response depends on factors such as nanotube diameter, chirality, and prior charge injection history.

Notably, the long-term persistence of these shape changes was observed, which can be attributed to the accumulation of structural defects and the associated strain, potentially enabling memory-like charge confinement.

The choice of substrate can shift the work function of MoS2 nanotubes by several hundred millivolts, directly influencing Schottky barrier heights, charge injection, and contact resistance - findings critical for contact engineering and device fabrication.

Overall, these findings highlight the importance of nanoscale structural and electrical characterization for understanding and engineering charge transport in MoS2 nanotubes. This insight is essential for the development of defect-tolerant, high-performance devices based on transition metal dichalcogenides.

超低功耗、高性能计算设备的需求持续推动电子技术的迭代升级。在新兴材料中，二硫化钼（molybdenum disulfide, MoS₂）凭借其优异的电子与量子特性受到广泛关注，尤其是从块体结构向二维结构转变时。尽管二硫化钼单层已被广泛研究，但二硫化钼纳米管的电学行为仍有待深入探索。

本研究针对通过化学气相输运（chemical vapor transport）合成的圆柱形与塌陷型二硫化钼纳米管展开探究，结果显示其缺陷密度较低且界面手性结构连续。研究发现，塌陷型纳米管的表面形貌不均匀且带有褶皱，凸起区域的导电性优于凹陷区域。相比之下，高曲率边缘处的导电性变化显著，范围从绝缘态到高导电态，表明此处存在局域电子限域效应。

电荷注入可显著改变纳米管的表面电势。由于二硫化钼面内与面外电导率存在极强各向异性，注入的电荷载流子主要沿横向传输。但该传输过程会受到缺陷、边缘终止结构以及界面应变等结构缺陷的影响。此外，相互重叠的纳米管与表面薄片可通过电荷俘获、静电门控以及应变诱导散射等机制改变局部电子特性。

进一步研究发现，电荷注入可使圆柱形与塌陷型纳米管产生可逆的几何形变。这类形变表现为沿纳米管轴向的螺旋扭转与渐进式塑性变形，其成因可归结为手性结构固有的逆压电效应的旋转分量。该响应的幅度取决于纳米管直径、手性参数以及先前的电荷注入历史等因素。

值得注意的是，研究观察到这类形变可长期保持，其成因可归结为结构缺陷的累积与伴随的应变，这有望实现类记忆型电荷限域效应。

衬底的选择可使二硫化钼纳米管的功函数偏移数百毫伏，直接影响肖特基势垒高度、电荷注入与接触电阻——该发现对接触工程与器件制备具有重要指导意义。

综上，本研究结果凸显了纳米尺度结构与电学表征对于理解并调控二硫化钼纳米管中电荷传输过程的重要性。该认知对于开发基于过渡金属二硫族化合物（transition metal dichalcogenides）的缺陷容忍型、高性能器件至关重要。