Schematic representation of the GIWAXS measurements on HA and VA MoS₂ layers.

The last few decades faced on the fabrication of advanced engineering materials involving also different composites. Here, we report on the fabrication of few-layer molybdenum disulfide on top of thin polycrystalline diamond substrates with a high specific surface area. In the method, pre-deposited molybdenum coatings were sulfurized in a one-zone furnace at ambient pressure. As-prepared MoS₂ layers were characterized by several techniques including grazing-incidence wide-angle X-ray scattering, atomic force microscopy, scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. We found out that the initial thickness of Mo films determined the final c-axis crystallographic orientation of MoS₂ layer as previously observed on other substrates. Even though it is well-known that Mo diffuses into diamond at elevated temperatures, the competing sulfurization applied effectively suppressed the diffusion and a chemical reaction between molybdenum and diamond. In particular, a Mo₂C layer does not form at the interface between the Mo film and diamond substrate. The combination of diamond high specific surface area along with a controllable layer orientation might be attractive for applications, such as water splitting or water disinfection.

The oxidation of MoS₂ with a simultaneous decrease of MoS₂ content.

Research on two-dimensional (2D) atomic crystals is one of the highly progressive topics in (opto)electronics, as the van der Waals (vdW) interactions enable integration of 2D crystals with a broad range of materials. Organic π-conjugated molecules offer new opportunities for creating the so-called “hybrid” vdW heterostructures, in which their anisotropy adds an extra degree of functional possibilities. Moreover, it was found that in the case of organic molecules, the 2D substrate changes the molecular orientation, which in turn can enhance the overall optoelectronic properties. However, the reorientation of the molecules has been until now studied solely on the graphene underlayer that restrained its applicability to a broader range of materials. Here, we study the molecular orientation of diindenoperylene (DIP), a representative of rodlike organic semiconductors, on the MoS₂ monolayer. Our results show that DIP forms separate islands on the top of the MoS₂ monolayer with lying-down orientation of the molecules. We combine the grazing-incidence X-ray diffraction technique with atomistic simulations to reveal the exact molecular arrangement on the atomically thin underlayer. We also investigate optical absorption spectra for different thicknesses of the DIP layer, as they are of fundamental importance for various applications in organic-based optoelectronics.