Courtney E, Conroy M, Bangert U
TEMUL, Department of Physics, School of Natural Sciences & Bernal Institute, University of Limerick, Limerick, Ireland.
J Microsc. 2020 Sep;279(3):274-281. doi: 10.1111/jmi.12902. Epub 2020 May 30.
The behaviour of palladium and nickel deposited on mechanically exfoliated samples of 2D transition metal dichalcogenides (MoS , WS and WSe ) via e-beam evaporation was investigated. Sputtering of metals on the 2D flakes allowed for interaction of the metal and TMD to be investigated on the Å scale in an aberration-corrected transmission electron microscope. Through low energy sputtering, metals can be deposited on 2D materials without causing damage to the thin flakes. The material's interaction is investigated on the atomic scale via high resolution scanning transmission electron microscopy in high angle annular dark-field imaging. Initially, the effect of thermal annealing on the stability of the Pd-2D interaction was investigated, revealing the remarkable difference in particle stability between the 2D materials. Nickel deposition however only resulted in oxidised amorphous particles. The oxide particles' cross-sectional area and circularity were independent of the TMD substrate thickness, type, or deposition rate. LAY DESCRIPTION: Understanding the interaction between metals and 2D materials is imperative for future device functionalisation. Palladium and nickel were deposited on samples of 2D transition metal dichalcogenides (MoS , WS and WSe ) via e-beam evaporation. Low energy introduced metal to the 2D materials without causing damage to the thin flakes. The metal-2D interaction was investigated on the Å scale via high resolution scanning transmission electron microscopy in high angle annular dark-field imaging. The interaction between the Pd and the 2Ds was investigated to see whether Pd is a viable contact solution for TMD materials and to study the metal-2D interaction at the atomic level. Effect of annealing and heat on the stability of the Pd-2D interaction was investigated, showing Pd-WSe to have high particle stability up to 200 °C. In contrast, the Pd-MoS and Pd-WS had lower particle stability when heated, revealing particle agglomeration and changes. Nickel was found to oxidise into amorphous oxide particles quickly after deposition. The oxide particles' characteristics were independent of the TMD substrate thickness andtype, and independent of the rate at which metal was deposited.
研究了通过电子束蒸发沉积在二维过渡金属二硫属化物（MoS₂、WS₂和WSe₂）机械剥离样品上的钯和镍的行为。在二维薄片上溅射金属使得能够在像差校正透射电子显微镜中在埃尺度上研究金属与过渡金属二硫属化物的相互作用。通过低能溅射，可以将金属沉积在二维材料上而不会对薄片造成损坏。通过高分辨率扫描透射电子显微镜在高角度环形暗场成像中在原子尺度上研究材料的相互作用。最初，研究了热退火对钯与二维材料相互作用稳定性的影响，揭示了二维材料之间颗粒稳定性的显著差异。然而，镍沉积仅产生氧化的非晶颗粒。氧化物颗粒的横截面积和圆度与过渡金属二硫属化物衬底的厚度、类型或沉积速率无关。层次描述：了解金属与二维材料之间的相互作用对于未来器件功能化至关重要。通过电子束蒸发将钯和镍沉积在二维过渡金属二硫属化物（MoS₂、WS₂和WSe₂）样品上。低能将金属引入二维材料而不会对薄片造成损坏。通过高分辨率扫描透射电子显微镜在高角度环形暗场成像中在埃尺度上研究金属与二维材料的相互作用。研究了钯与二维材料之间的相互作用，以确定钯是否是过渡金属二硫属化物材料可行的接触解决方案，并在原子水平上研究金属与二维材料的相互作用。研究了退火和加热对钯与二维材料相互作用稳定性的影响，表明钯 - 硒化钨在高达200°C时具有高颗粒稳定性。相比之下，钯 - 硫化钼和钯 - 硫化钨在加热时颗粒稳定性较低，显示出颗粒团聚和变化。发现镍在沉积后迅速氧化成非晶氧化物颗粒。氧化物颗粒的特性与过渡金属二硫属化物衬底的厚度和类型无关，也与金属沉积速率无关。
