Transistors based on semiconducting transition metal dichalcogenides can, in theory, offer high carrier mobilities, strong spin–orbit coupling and inherently strong electronic interactions at the quantum ground states. This makes them well suited for use in nanoelectronics at low temperatures. However, creating robust ohmic contacts to transition metal dichalcogenide layers at cryogenic temperatures is difficult. As a result, it is not possible to reach the quantum limit at which the Fermi level is close to the band edge and thus probe electron correlations in the fractionally filled Landau-level regime. Here we show that ohmic contacts to n-type molybdenum disulfide can be created over a temperature range from millikelvins to 300 K using a window-contacted technique. We observe field-effect mobilities of over 100,000 cm² V⁻¹ s⁻¹ and quantum mobilities of over 3,000 cm² V⁻¹ s⁻¹ in the conduction band at low temperatures. We also report evidence for fractional quantum Hall states at filling fractions of 4/5 and 2/5 in the lowest Landau levels of bilayer molybdenum disulfide.

理论上，基于半导体过渡金属二硫化物的晶体管可以提供高载流子迁移率、强自旋轨道耦合和量子基态下固有的强电子相互作用。这使得它们非常适合在低温下用于纳米电子学。然而，在低温下创建坚固的欧姆接触以过渡金属二硫化物层是困难的。因此，不可能达到费米能级接近能带边缘的量子极限，从而在分数填充的朗道能级状态中探测电子相关性。在这里，我们展示了使用窗口接触技术，可以在从毫开尔文到 300 K 的温度范围内产生与 n 型二硫化钼的欧姆接触。在低温下，我们在导带中观察到超过 100,000 cm^{2 V-1 s-1} 的场效应迁移率和超过 3,000 cm^{2 V-1 s-1} 的量子迁移率。我们还报告了在双层二硫化钼的最低 Landau 水平中 4/5 和 2/5 填充级分的分数量子霍尔态的证据。