Wafer-scale Quasi-van der Waals Epitaxy of Mixed-Dimensional III-Nitrides by Metal Organic Chemical Vapor Deposition 

Seokho Moon
Pohang University of Science and Technology, Pohang, Republic of Korea

_______________________________________

Quasi-van der Waals (QvdW) epitaxy, where a 3D thin film is grown on a 2D material via weak interfacial interactions, has emerged as a powerful approach for overcoming lattice-mistmatch constraints in heteroepitaxy. Unlike conventional epitaxy, where strong chemical bonding imposes strict requirements on lattice and thermal compatibility, QvdW epitaxy allows the growth of high-quality thin films by minimizing interfacial strain. Additionally, this method facilitates the mechanical release and transfer of epitaxial thin films, broadening their applicability in flexible and heterogeneous integration.

Here, we employ hexagonal boron nitride (h-BN) as a 2D material platform for wafer-scale QvdW epitaxy of III-Nitride thin films. A key challenge in this process is preserving the structural integrity and surface morphology of h-BN, which directly influences the crystalline quality of overlying III-Nitride films. Through comprehensive and systematic spectroscopic and structural analysis, including synchrotron radiation-based X-ray measurements and high-resolution transmission electron microscopy, we establish optimal growth conditions that maintain the stability of h-BN while achieving high-quality III-Nitride films. Furthermore, we investigate how key growth parameters, such as reactor temperature, influence the epitaxial structure and film properties, providing critical insights into the fundamental mechanisms governing QvdW epitaxy of III-Nitrides. These findings offer a pathway toward scalable, high-performance III-Nitride heterostructures, advancing their potentials in optoelectronics and power electronics.

Email: moon0603@postech.ac.kr