Seminarium Fizyki Ciała Stałego

Hexagonal boron nitride (h-BN) is an attractive 2D material for possible applications in electronic and optoelectronic devices based on van der Waals heterostructures, but direct growth of high-quality hBN on the wafer-scale is still the bottleneck for future successful implementation of hBN in industry. Although the synthesis of h-BN by MOVPE has already been reported, there is a fundamental lack in understanding of many basic aspects of this process. In particular, the role of the substrate off-cut, although known to be of major importance for the growth of other materials, has not been fully addressed so far.In the first part of this presentation, I will present our recent results that address the influence of the sapphire substrate off-cut angle on the final quality of h-BN obtained in a two-step growth procedure. The main process starts with a self-limiting continuous growth (CFG) of a BN buffer followed by flow-modulated epitaxy (FME) in the second step and is used to study samples with different off-cuts angles for three different CFG times. Based on results obtained by x-ray diffraction and reflectometry, Raman and Fourier-transform spectroscopy, atomic force microscopy and scanning electron microscopy (SEM), we find that a substrate with optimal off-cut angle clearly yields the highest quality of h-BN layers. Samples with this off-cut have the lowest amount of debris on the surface, most intense x-ray diffraction signal, minimal Raman phonon linewidth and thinnest amorphous BN part.In the second part, I will discuss the relationship between the angular arrangement of the h-BN layers and the surface of the sapphire substrate (off-cut/offset analysis).M. Tokarczyk, et al. 2D Materials 10, 025010 (2023).UwagaSeminarium w trybie HybrydowymFaculty of Physics room 0.06link to remote mode:https://zoom.us/j/7218838148szczegóły patrz instrukcja :instrukcja: (pdf file)AttentionThe seminar in the Hybrid modeFaculty of Physics room 0.06for details see instruction :instruction: (pdf file)