Transition metal dichalcogenides (TMDs) are layered semiconducting van der Waal crystals and promising materials for a wide range of electronic and optoelectronic devices. Realizing practical electrical and optoelectronic device applications requires a connection between a metal junction and a TMD semiconductor. Hence, a complete understanding of electronic band alignments and the potential barrier heights governing the transport through a metal-TMD-metal junction is critical. But, there is a knowledge gap; it is not clear how the energy bands of a TMD align while in contact with a metal as a function of the number of layers. In pursuit of removing this knowledge gap, we have performed conductive atomic force microscopy (CAFM) of few layered (1-5) MoS2 immobilized on ultra-flat conducting Au surfaces (root mean square (RMS) surface roughness <0.2 nm) and indium tin oxide (ITO) substrate (RMS surface roughness <0.7 nm) forming a vertical metal (conductive-AFM tip)-semiconductor-metal device. We have observed that the current increases as the number of layers increases up to 5 layers. By applying Fowler-Nordheim tunneling theory, we have determined the barrier heights for different layers and observed that the barrier height decreases as the number of layers increases. Using density functional theory (DFT) calculation, we successfully demonstrated that the barrier height decreases as the layer number increases. By illuminating the TMDs on a transparent ultra-flat conducting ITO substrate, we observed a reduction in current when compared to the current measured in the dark, hence demonstrating negative photoconductivity. Our study provides a fundamental understanding of the local electronic and optoelectronic behaviors of TMD-metal junction, and may pave an avenue toward developing nanoscale electronic devices with tailored layer-dependent transport properties.
Tunnel-Barrier-Engineered Ultrafast Demagnetization and Spin Transport in Graphene-Based Heterostructures
S. N. Bose National Center for Basic Sciences（S.N. 玻色基础科学国家中心）；Indian Institute of Science Education and Research Kolkata（加尔各答印度科学与教育研究所）；Uppsala University（乌普萨拉大学）
Effect of interfacial Fe3O4 nanoparticles on the microstructure and mechanical properties of textured alumina densified by ultrafast high-temperature sintering
Probing Interfacial Spin Dynamics and Temperature Dependent Asymmetry in Spin Pumping Across Ni80Fe20/Cu/Cr1.12Te2 Interfaces
Department of Physics, Indian Institute of Technology Kanpur（印度坎普尔理工学院物理系）；Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University（南洋理工大学国立教育学院自然科学与科学教育）
我们证明了一个大面积的石墨烯钝化层的机械转移的非晶Ga $_2$ O $_3$合成液体Ga金属。在SiO $_2$/Si上的毫米级钝化和裸石墨烯的温度依赖性电测量的比较表明，钝化的石墨烯保持其应用所期望的高场效应迁移率。令人惊讶的是，在低于220 K的温度范围内，钝化石墨烯中的温度依赖性电阻率降低，这是由于高介电常数Ga $_2$ O $_3$对SiO $_2$的表面光学声子模式的屏蔽和Ga $_2$ O $_3$的相对高的特征声子频率的相互作用。拉曼光谱和电学测量表明Ga $_2$ O $_3$钝化还保护石墨烯免于进一步处理，例如Al $_2$ O $_3$的等离子体增强原子层沉积。
Controlling Terahertz Spintronic Photocurrents in 2D-Semiconductor|Ferromagnet Heterostructures through a Functional Hybrid Interface
Freie Universität Berlin（柏林自由大学）；Forschungszentrum Jülich（于利希研究中心）；Max Planck Institute of Microstructure Physics（马克斯·普朗克微观结构物理研究所）；National University of Singapore（新加坡国立大学）；A*STAR (Agency for Science, Technology and Research)（新加坡科技研究局）；Nanyang Technological University（南洋理工大学）；Max-Born-Institute for Non-Linear optics（马克斯·玻恩非线性光学研究所）；Centre for quantum technologies（量子技术中心）
