Work

Van der Waals Epitaxy of High‐Quality Transition Metal Dichalcogenides on Single‐Crystal Hexagonal Boron Nitride

Year: 2024

Type: article

Abstract: Van der Waals (vdW) heterostructures comprising of transition metal dichalcogenides (TMDs) and hexagonal boron nitride (h‐BN) are promising building blocks for novel 2D devices. The vdW epitaxy provides a straightforward integration method for fabricating high‐quality TMDs/h‐BN vertical heterostructures. In this work, the vdW epitaxy of high‐quality single‐crystal HfSe 2 on epitaxial h‐BN/sapphire substrates by chemical vapor deposition is demonstrated. The epitaxial HfSe 2 layers exhibit a uniform and atomically sharp interface with the underlying h‐BN template, and the epitaxial relationship between HfSe 2 and h‐BN/sapphire is determined to HfSe 2 (0001)[110]//h‐BN (0001)[100]//sapphire (0001)[100]. Impressively, the full width at half maximum of the rocking curve for the epitaxial HfSe 2 layer on single‐crystal h‐BN is as narrow as 9.6 arcmin, indicating an extremely high degree of out‐plane orientation and high crystallinity. Benefitting from the high crystalline quality of HfSe 2 epilayers and the weak interfacial scattering of HfSe 2 /h‐BN, the photodetector fabricated from the vdW epitaxial HfSe 2 on single‐crystal h‐BN shows the best performance with an on/off ratio of 1 × 10 4 and a responsivity up to 43 mA W −1 . Furthermore, the vdW epitaxy of other TMDs such as HfS 2 , ZrS 2 , and ZrSe 2 is also experimentally demonstrated on single‐crystal h‐BN, suggesting the broad applicability of the h‐BN template for the vdW epitaxy.

Source: Small Methods

DOI: 10.1002/smtd.202401296