“Van der Waals layer promoted heteroepitaxy in sputter-deposited thin films”
Crystallinity is an important material characteristic that often dictates properties and life-time performance of bulk as well as low-dimensional materials. Common approaches to improve crystallinity, increase grain size, and grain orientation in thin solid films involve the use of single-crystalline substrates, high substrate temperatures (which tend to enhance surface mobility) combined with low deposition fluxes. It is known since 1980s that highly crystalline thin films can be grown on van der Waals (vdW) surfaces and vice versa, phenomenon referred to as vdW epitaxy. Recent studies have also demonstrated ‘remote epitaxy’, which refers to homoepitaxial growth across a vdW buffer layer such as two-dimensional (2D) graphene.
In this talk, I will present results, which suggest that trigonal-structured 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, remote-epitaxy yields better crystalline quality than homoepitaxy. These results, if validated, can facilitate low-temperature growth of crystalline thin films of a variety of materials.
