Study on Enhancing Epitaxial crystal quality Controlling Defect Density in Anchored Remote Epitaxy

Abstract

Remote epitaxy is a next-generation epitaxial technology that forms thin films by transmitting the lattice potential of a substrate through an atomically thin two-dimensional （2D） material. This method leverages weak van der Waals interactions for easy film exfoliation, enablissng the reuse of expensive single-crystal substrates and offering significant advantages for heterogeneous integration and flexible electronic applications. The successful implementation of this technique requires the introduction of a single layer 2D material, such as pristine graphene, which can effectively permeate the potential field of the substrate. However, due to the low surface reactivity of defect-free graphene, a low nucleation density occurs during Metal-Organic Chemical Vapor Deposition （MOCVD）, potentially leading to degraded crystallinity and non-uniform film formation. In this study, we propose a method to enhance the growth quality of Gallium Nitride （GaN） by locally converting 𝑠𝑝2 bonds of graphene into 𝑠𝑝3 bonds via ozone treatment to control defect density, thereby creating stable nucleation sites on the 2D material. Single-layer graphene was wet-transferred onto a sapphire （0001） substrate and subjected to UV-ozone treatment to regulate surface defect density. The resulting structural changes were quantitatively evaluated using Raman spectroscopy. Subsequently, GaN thin films were grown using the MOCVD process. The graphene surface was characterized post-ozone treatment using Raman, X-ray photoelectron spectroscopy （XPS）, and Atomic force microscopy （AFM）, while the crystallinity of the grown films was analyzed via X-ray Diffraction （XRD） and Scanning Electron Microscopy （SEM）. The experimental results confirmed the existence of a critical defect density in anchored remote epitaxy that utilizes defect-based nucleation while maintaining the orientation and crystallinity of the thin film. This study suggests that controlling the Yujin Park. Study on Enhancing Epitaxial crystal quality controlling defect density Anchored remote epitaxy. College of Electrical Engineering and Computer Science, Department of Electrical Engineering and Computer Science. 2026. 45p. Advisor Prof. Dong-Seon Lee defect density of the 2D interface is a highly effective strategy for nucleation control in achieving high- quality remote epitaxial films. ⓒ 2026 Yujin Park ALL RIGHTS RESERVED