About event
Crystallinity is an important material characteristic that dictates properties and hence performance of materials. Microstructural evolution in sputter-deposited thin films is generally influenced by the deposition parameters, such as partial pressure of the reactive gases, substrate temperature, deposition fluxes, and the target composition. Common approaches to improve crystallinity, to increase grain size and the grain orientation in thin solid films involve the use of single-crystalline substrates, high substrate temperatures combined with low deposition fluxes, and energetic ion beams.
In this talk, I will present our recent results demonstrating improved crystallinity in thin films sputter-deposited on substrates covered with van der Waals (vdW) layers. We show that Ta2C thin films grown on Ta2C(0001) covered with hexagonal boron nitride (hBN), a vdW-bonded material, are more highly oriented than those films grown directly on bare Ta2C(0001) under identical deposition conditions. That is, heteroepitaxial growth across a vdW layer seemingly yields better crystalline quality than homoepitaxy. We observe similar highly-oriented growth of face-centered cubic Pd, body centered cubic Mo, and hexagonal MoS2 thin films on hBN-covered substrates. Our results provide new insights into the role of vdW layers on the kinetics of nucleation and growth during vapor phase deposition. Our approach may potentially be attractive for the growth of highly-oriented thin films on arbitrary substrates.
