The competing orders arising in a two-dimensional limit are the key to understanding unconventional superconductivity. The monolayer NbSe₂ possessing a charge density wave (CDW) and superconducting orders provides a playground to study unconventional superconductivity. Here we fabricate an ultrathin 2H–NbSe₂ device based on the mechanical exfoliation method and our electrode transfer technique. Detailed four-lead and two-lead transport measurements are performed in the ultrathin sample. The superconducting transition ( T _c ) at 4.3 K and CDW transition at 70 K are found in the sample, consistent with the literature report for ultrathin 2H–NbSe₂. The superconducting gap (Δ) of ultrathin 2H–NbSe₂ is estimated by fitting the two-lead transport spectroscopy with the Blonder–Tinkham–Klapwijk (BTK) theory. We found that Δ( T ) exhibits a BCS-like temperature dependence with Δ 1.1 meV at 0 K and . Meanwhile the gap-like features persist in the normal state and become unresolvable with the increasing temperature and magnetic field, suggesting a possible precursor superconductivity similar to the cuprate superconductors. Our results provide a new insight into superconductivity in ultrathin 2H–NbSe₂.

二维极限中产生的竞争订单是理解非常规超导性的关键。具有电荷密度波（CDW）和超导阶数的单层NbSe ₂为研究非常规超导性提供了场所。在这里，我们基于机械剥落法和我们的电极转移技术制造了超薄2H–NbSe ₂器件。在超薄样品中执行详细的四线和两线传输测量。在样品中发现了4.3 K处的超导转变（T _c）和70 K处的CDW转变，这与超薄2H–NbSe ₂的文献报道一致。超薄2H–NbSe ₂的超导间隙（Δ） 通过用Blonder–Tinkham–Klapwijk（BTK）理论拟合两线传输光谱来估算。我们发现Δ（T）在0 K和时表现出BCS样的温度依赖性，其Δ1.1 meV 。同时，间隙状特征在正常状态下保持不变，并且随着温度和磁场的增加而变得不可分辨，这表明可能存在类似于铜酸盐超导体的前体超导性。我们的结果为超薄2H–NbSe _2中的超导性提供了新的见解。