AI 中文总结
研究通过结合 IV 表征、LBIC 映射和偏置相关 KPFM 的综合框架，解析少层 MoS2 基器件接触特性，可识别势垒类型及不对称性，热退火可降阻，此方法能用于其他二维半导体 - 金属系统。
AI 中文摘要
金属与二维半导体（如二硫化钼（MoS2））之间的电接触对器件性能至关重要，但其微观性质难以用单一表征技术解析。本文提出一个综合实验框架，结合电流 - 电压（IV）表征、激光束诱导电流（LBIC）映射和偏置相关开尔文探针力显微镜（KPFM），以全面解析少层 MoS2 基两端器件在环境条件下的接触特性。IV 测量给出宏观传输特性，LBIC 以微米空间分辨率映射局部光电流响应，KPFM 在施加静态偏置下提供纳米级分辨的电势分布。将此框架应用于三个代表性器件，能明确识别主导势垒是肖特基型还是隧道型，并确定两个接触之间的不对称性。还表明热退火显著降低总电阻，而接触势垒仍是电阻的主要来源。该方法可直接应用于其他二维半导体 - 金属系统。
英文摘要
Electrical contacts between metals and two-dimensional (2D) semiconductors such as molybdenum disulfide (MoS2) critically govern device performance, yet their microscopic nature remains difficult to disentangle using any single characterization technique. Here we present an integrated experimental framework that combines current-voltage (IV) characterization, laser beam induced current (LBIC) mapping, and bias-dependent Kelvin probe force microscopy (KPFM) to comprehensively resolve the contact properties of few-layer MoS2-based two-terminal devices under ambient conditions. IV measurements deliver macroscopic transport characteristics as a function of bias voltage and illumination conditions. LBIC maps the local photocurrent response with micrometer spatial resolution, revealing the position and nature of internal electric fields at MoS2-metal interfaces. KPFM, operated under an applied static bias rather than in the conventional work-function mode, provides nanoscale-resolved potential distributions that quantify the relative magnitudes and spatial locations of contact barriers. We apply this framework to three representative devices - one exhibiting ohmic-like and two exhibiting diode-like contact behavior - and demonstrate that the combined analysis can unambiguously identify whether the dominant barrier is of Schottky or tunnel type and determine the asymmetry between the two contacts. We further demonstrate that thermal annealing significantly reduces the total resistance, while contact barriers remain the dominant source of resistance. The methodology is directly transferable to other 2D semiconductor-metal systems and provides a practical yet comprehensive route toward a quantitative microscopic understanding of 2D device contacts.
