In-plane anisotropy in van der Waals epitaxial MoS2 on MoO2(010)

Transition metal dichalcogenide based 2D/2D or 2D/3D van der Waals heterostructures exhibit superior properties for high-performance electronics, tunneling transistors, and catalysts. Here, we report on the fabrication of high quality 2D/3D MoS 2 /MoO 2 heterostructures with an atomic clean interface by one-step chemical vapor deposition. Optical microscopy, atomic force microscopy, Raman spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy measurements reveal the high-quality of as-grown samples and the specific epitaxial relationship between MoS 2 and MoO 2 : MoS 2 [ 1 ¯ 1 ¯ 20]//MoO 2 [001] and MoS 2 [ 1 ¯ 100]//MoO 2 [201]. Photoluminescence and Kelvin probe force microscopy measurements combined with density functional theory calculations confirm the interfacial charge transfer from MoS 2 to the underlying MoO 2 . Furthermore, MoO 2 induced in-plane anisotropy in MoS 2 was revealed using angle-resolved polarized Raman and photoluminescence spectroscopy with anisotropic ratios of 1.27 (Raman) and 1.29 (photoluminescence), respectively, which is most possibly attributed to anisotropic interfacial charge interactions. Our findings provide an excellent platform for the investigation on interfacial effects. Moreover, the in-plane anisotropy in MoS 2 induced by MoO 2 has expanded the application of isotropic MoS 2 in the polarization-dependent fields.