MoS2/h-BN heterostructures: controlling MoS2 crystal morphology by chemical vapor deposition

Tuning the properties of van der Waals heterostructures based on alternating layers of two-dimensional materials is an emerging field of research with implications for electronics and photonics. Hexagonal boron nitride (h-BN) is an attractive insulating substrate for two-dimensional materials as it may exert less influence on the layer’s properties than silica. In this work, MoS2 layers were deposited by chemical vapor deposition (CVD) on thick h-BN flakes mechanically exfoliated deposited on Si/SiO2 substrates. CVD affords the controllable, large-scale preparation of MoS2 on h-BN alleviating shortcomings of manual mechanical assembly of such heterostructures. Electron microscopy revealed that in-plane and vertical to the substrate MoS2 layers were grown at high yield, depending on the sample preparation conditions. Raman and photoluminescence spectroscopy were employed to assess the optical and electronic quality of MoS2 grown on h-BN as well as the interactions between MoS2 and the supporting substrate. Compared to silica, MoS2 layers grown on h-BN are less prone to oxidation and are subjected to considerably weaker electronic perturbation.