Tungsten diselenide (WSe₂) is attracting attention because of its superior electronic and optoelectronic properties. In recent years, the number of research works related to the WSe₂‐based field‐effect transistors (FETs) has increased dramatically. Nonetheless, the performance of 2D WSe₂ is influenced sensitively by metal–semiconductor (MS) interface states, where Fermi‐level pinning is substantial. This research explores Fermi‐level depinning by doping with an n‐type polymer. In this work, spin‐coated polyvinyl alcohol (PVA) is used as an n‐type dopant for achieving low‐contact‐resistance WSe₂ FETs in cases of both high‐work‐function (Pd) and low‐work‐function (In) metals. Interestingly, the increase in the Schottky barrier height resulting from the application of PVA gives rise to Fowler–Nordheim tunneling for a doped Pd‐WSe₂ contact. By contrast, only direct tunneling is observed for an In‐WSe₂ contact irrespective of whether the dopant is used. The barrier‐height modification after doping reveals that the improvement of the contact resistance is correlated to the enhancement of tunneling current after doping, which is consistent with the measurement results. This work suggests a practical direction for contact engineering of future WSe₂‐based electronic devices and expands the current understanding of charge transport at the MS contact when a polymeric n‐type dopant is applied.

中文翻译：

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通过聚合物掺杂控制金属-WSe2界面的肖特基势垒和接触电阻

二硒钨（WSe ₂）由于其优异的电子和光电性能而备受关注。近年来，与基于WSe ₂的场效应晶体管（FET）相关的研究数量急剧增加。但是，2D WSe ₂的性能受到金属-半导体（MS）界面状态的敏感影响，其中费米能级固定作用很大。这项研究探索了通过掺杂n型聚合物进行的费米能级钉扎。在这项工作中，使用旋涂聚乙烯醇（PVA）作为n型掺杂剂以实现低接触电阻WSe ₂高功能金属（Pd）和低功能金属（In）的FET。有趣的是，由于PVA的应用，肖特基势垒高度的增加导致了掺杂Pd-WSe ₂接触的Fowler-Nordheim隧穿。相比之下，无论是否使用掺杂剂，对于In-WSe ₂触点仅观察到直接隧穿。掺杂后势垒高度的变化表明，接触电阻的改善与掺杂后隧穿电流的增加有关，这与测量结果一致。这项工作为未来WSe _2的接触工程提出了一个实用的方向。基于电子的设备，并在应用聚合n型掺杂剂时扩展了对MS接触处电荷传输的当前理解。