Abstract The large Schottky barriers formed at metal–semiconductor junctions severely limit the development of transition metal dichalcogenide (TMDC)-based ultrathin electronics and optoelectronics. Various approaches to create Ohmic contacts at TMDC and metal interface have been developed, including contact phase engineering, contact doping, buffer layer engineering, and contact integration engineering. Here, we report degenerate electron doping of mono- and bi-layer tungsten diselenide (WSe2) by a molecular organometallic donor, [RuCp*(mes)]2. In-situ evaporation of [RuCp*(mes)]2 molecules onto WSe2 field-effect transistors in vacuum leads to a remarkably diminished gate dependence of the transport property and a large enhancement of electrical conductance by five orders of magnitude, implying the great potential of this doping approach in tuning the Schottky barrier for TMDC devices. The interfacial electronic structure at the WSe2–dopant interface was revealed through the combination of in-situ photoelectron spectroscopy investigations and theoretical calculations. Moreover, the doped device is found to be robust in oxygen and nitrogen atmosphere and also moderately stable in humid air, which is favorable in device applications.

中文翻译：

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二维二硒化钨中的简并电子掺杂与二聚有机金属还原剂

摘要 金属-半导体结处形成的大肖特基势垒严重限制了基于过渡金属二硫属化物（TMDC）的超薄电子和光电子的发展。已经开发了各种在 TMDC 和金属界面上创建欧姆接触的方法，包括接触相位工程、接触掺杂、缓冲层工程和接触集成工程。在这里，我们报告了分子有机金属供体 [RuCp*(mes)]2 对单层和双层二硒化钨 (WSe2) 的简并电子掺杂。[RuCp*(mes)]2 分子在真空中原位蒸发到 WSe2 场效应晶体管上，导致传输特性的栅极依赖性显着降低，电导率大幅提高五个数量级，这意味着这种掺杂方法在调整 TMDC 器件的肖特基势垒方面具有巨大潜力。通过原位光电子能谱研究和理论计算的结合，揭示了 WSe2-掺杂剂界面的界面电子结构。此外，发现掺杂器件在氧气和氮气气氛中是稳健的，并且在潮湿空气中也适度稳定，这在器件应用中是有利的。