van der Waals Self-Epitaxial Growth of Inch-Sized Superconducting Niobium Diselenide Films

Abstract

Ultrathin superconducting films are the basis of superconductor devices. van der Waals (vdW) NbSe 2 with noncentrosymmetry exhibits exotic superconductivity and shows promise in superconductor electronic devices. However, the growth of inch-scale NbSe 2 films with layer regulation remains a challenge because vdW structural material growth is strongly dependent on the epitaxial guidance of the substrate. Herein, a vdW self-epitaxy strategy is developed to eliminate the substrate driving force in film growth and realize inch-sized NbSe 2 film growth with thicknesses from 2.1 to 12.1 nm on arbitrary substrates. The superconducting transition temperature of 5.1 K and superconducting transition width of 0.30 K prove the top homogeneity and quality of superconductivity among all of the synthetic NbSe 2 films. Coupled with a large area and substrate compatibility, this work paves the way for developing NbSe 2 superconductor electronics.

Synthesis of NbSe2/Bilayer Nb‐Doped WSe2 Heterostructure from Exfoliated WSe2 Flakes

“…The heterostructure exhibits the characteristic elements of Nb, W, and Se. The binding energies of the Nb 3 d core levels were designated as 3 d 3/2 (203 eV) and 3 d 5/2 (206 eV), in line with the spectral patterns of Nb in NbSe 2 , [ 34 ] corroborating the existence of an NbSe 2 layer within the heterostructure. It is noted that, the Nb elements mostly locate on the only NbSe 2 flake, while negligible Nb signals are observed on the other area (Figure S6, Supporting Information).…”

Low-dimensional van der Waals materials for linear-polarization-sensitive photodetection: materials, polarizing strategies and applications

“…Compared to low-dimensional single crystals, the preparation of polycrystalline vdWMs is much simpler and more cost-efficient, especially in terms of the scalable production. As proof, the wafer-scale preparation of polycrystalline Te [301], HfSe 2 [295], WTe 2 [302], NbSe 2 [303], h-BN [304], and even the ZnIn 2 S 4 /SnS van der Waals heterostructures [30] has been realized. Nevertheless, due to the mutual cancellation of the anisotropy of domains with arbitrary orientations, the overall symmetry of the polycrystalline system is generally improved.…”