High Schottky barrier heights at metal–semiconductor junctions due to Fermi-level pinning can degrade the performance of electronic devices and increase their energy consumption. Van der Waals contacts between metals and two-dimensional semiconductors without Fermi-level pinning are theoretically possible, but have not been achieved due to the presence of interactions such as interface defects and orbital overlap. Here we show that interaction- and defect-free van der Waals contacts can be formed between a range of metals and two-dimensional semiconductors via a metal deposition process that uses a selenium buffer layer. Our contacts obey the Schottky–Mott rule and have a Fermi-level pinning of –0.91. A comparison between the van der Waals contacts and typical direct metal contacts reveals differences in interface gap distances, band bending and electrical characteristics. Using gold van der Waals contacts, we fabricate p-type tungsten diselenide field-effect transistors that exhibit stable operation with on/off ratio of 10⁶, mobility of 155 cm² (V s)^–1, contact resistance of 1.25 kΩ μm and Schottky barrier height of 60 meV.

由于费米能级钉扎导致的金属-半导体结处的高肖特基势垒高度会降低电子设备的性能并增加其能耗。理论上，金属和二维半导体之间没有费米能级钉扎的范德华接触是可能的，但由于界面缺陷和轨道重叠等相互作用的存在，尚未实现。在这里，我们展示了通过使用硒缓冲层的金属沉积工艺，可以在一系列金属和二维半导体之间形成无相互作用和无缺陷的范德华接触。我们的联系人遵循肖特基-莫特规则，费米能级钉扎为 –0.91。范德华接触与典型的直接金属接触之间的比较揭示了界面间隙距离的差异，带弯曲和电气特性。使用金范德华触点，我们制造了 p 型二硒化钨场效应晶体管，该晶体管表现出稳定的操作，开/关比为 10^如图6所示，迁移率为155 cm ²  (V s) ^–1，接触电阻为1.25 kΩ μm，肖特基势垒高度为60 meV。