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Reynolds Dziobek-Garrett

Publications and source records attributed to Reynolds Dziobek-Garrett.

2 recordsLinked to original sources

Large-Area Deterministic Stamping of 2D Materials on Arbitrarily Patterned Surfaces

2D materials and their monolayers have attracted widespread interest by virtue of their unique electronic and optical properties. In addition to their remarkable physical characteristics, their atomically thin nature enables their integration in ultra-compact photonic and electronic devices, with potential for dynamic tunability via strain, charge carrier modulation or heterostructure engineering. While early research relied on micrometer-scale mechanically exfoliated flakes, recent advances, particularly gold-assisted exfoliation of transition metal dichalcogenides (TMDCs), have enabled the preparation of high-quality, large-area monolayers, opening new opportunities for scalable device integration. For the field of nanophotonics in particular, the ability to transfer large-area 2D materials onto both flat and patterned substrates is essential for the development of functional devices. However, existing transfer techniques are often limited in scalability, and compatibility with structured surfaces. Here, we present a versatile and reliable transfer method of large-area monolayers and hBN/monolayer heterostructures onto both flat and nanostructured substrates. Our approach, based on the physical properties of low-density polyethylene, preserves the intrinsic optical quality of the materials and is compatible with a variety of device architectures. We demonstrate its applicability by fabricating devices that modulate the photoluminescence of TMDC monolayers through the manipulation of the photonic environment, strain or electrical gating. We further demonstrate the fabrication of van der Waals heterostructures using the same method. By enabling clean transfer of a wide range of monolayers and heterostructures, this technique offers a practical pathway for the development of next-generation optoelectronic platforms with improved functionality, scalability, and tunability.

cond-mat.mes-hall↗

Exfoliation and Optical Properties of S=1 Triangular Lattice Antiferromagnet NiGa$_2$S$_4$

Two-dimensional (2D) van der Waals (vdW) materials have been an exciting area of research ever since scientists first isolated a single layer of graphene. Single layer magnetic materials can provide a pathway for vdW heterostructures with magnetic properties. While most of the magnetic vdW materials exhibit ordering transitions in the bulk, here we report a successful exfoliation of a triangular lattice S=1 antiferromagnet NiGa$_2$S$_4$, which already demonstrates exotic magnetism in the bulk material. We establish the number of layers of the material by atomic force microscopy (AFM) and detail a careful characterization using Raman and optical spectroscopy to demonstrate how the optical, electronic, and structural properties of NiGa$_2$S$_4$ change as a function of sample thickness. Optical measurements and electronic structure calculations of bulk versus monolayer NiGa$_2$S$_4$ confirm the material to be a Mott insulator with an electronic gap of about 1.5 eV, which slightly increases for layers below 10 L. We conclude with a theoretical analysis of the possibility of doping monolayer NiGa$_2$S$_4$ by proximity to a metal.

cond-mat.mtrl-sci↗