Christopher Serrano
Research Mentor: Xin Xie
Mentor Department: Physics, LSA
Author(s): Christopher Serrano, Xin Xie
Session: Session 6 (3:00 PM – 3:50 PM)
Presentation Type: Poster 10
Abstract
This project investigates the preparation of high-quality hexagonal boron nitride (hBN) layers for use as insulating spacers in van der Waals heterostructures designed to study transition metal dichalcogenide (TMD) nanomaterials for information science applications. Magnets remain fundamental to modern computing, and emerging two-dimensional magnetic systems based on TMDs offer new opportunities for tunable data processing platforms. To enable characterization of interlayer exchange coupling in these systems, we mechanically exfoliated hBN monolayers from bulk crystals onto SiO2 substrates using controlled Scotch tape exfoliation and Van der Waals adhesion techniques. SiO2 chips were fixed to glass slides, after which bulk crystals were distributed in a grid pattern and exfoliated at controlled rates. Optical microscopy at 10× and 100× magnification was used to identify potential hBN crystals via optical contrast and to estimate thickness. We observed that multilayer hBN flakes frequently formed adjacent to unprocessed bulk regions and sometimes near substrate borders. Often, large portions of chip surfaces contained fragmented or striated layers that reduced usable yield due to the stochastic nature of exfoliation. Despite these limitations, our methods produced high-quality hBN crystals for transfer and assembly of twisted multilayer heterostructures. These hBN layers provide a platform for controlling interlayer exchange and electronic coupling in TMD stacks, enabling optical studies of tunable two-dimensional magnetism relevant to next-generation information and computation technologies.
