We present the integration of epitaxial graphene with thin film dielectric materials for the purpose of graphene transistor development. The impact on epitaxial graphene structural and electronic properties following deposition of Al(2)O(3), HfO(2), TiO(2), and Ta(2)O(5) varies based on the choice of dielectric and deposition parameters. Each dielectric film requires the use of a nucleation layer to ensure uniform, continuous coverage on the graphene surface. Graphene quality degrades most severely following deposition of Ta(2)O(5), while the deposition if TiO(2) appears to improve the graphene carrier mobility. Finally, we discuss the potential of dielectric stack engineering for improved transistor performance.
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Sci Rep
January 2025
IBM T. J. Watson Research Center, Yorktown Heights, NY, 10598, USA.
The development of high-brightness electron sources is critical to state-of-the-art electron accelerator applications like X-ray free electron laser (XFEL) and ultra-fast electron microscopy. Cesium telluride is chosen as the electron source material for multiple cutting-edge XFEL facilities worldwide. This manuscript presents the first demonstration of the growth of highly crystalized and epitaxial cesium telluride thin films on 4H-SiC and graphene/4H-SiC substrates with ultrasmooth film surfaces.
View Article and Find Full Text PDFACS Nano
January 2025
School of Materials Science and Engineering, Peking University, Beijing 100871, People's Republic of China.
Single-crystal Au(111), renowned for its chemically inert surface, long-range "herringbone" reconstruction, and high electrical conductivity, has long served as an exemplary template in diverse fields, , crystal epitaxy, electronics, and electrocatalysis. However, commercial Au(111) products are high-priced and limited to centimeter sizes, largely restricting their broad applications. Herein, a low-cost, high-reproducible method is developed to produce 4 in.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan.
We present a versatile method for synthesizing high-quality molybdenum disulfide (MoS) crystals on graphite foil edges via chemical vapor deposition (CVD). This results in MoS/graphene heterostructures with precise epitaxial layers and no rotational misalignment, eliminating the need for transfer processes and reducing contamination. Utilizing in situ transmission electron microscopy (TEM) equipped with a nano-manipulator and tungsten probe, we mechanically induce the folding, wrinkling, and tearing of freestanding MoS crystals, enabling the real-time observation of structural changes at high temporal and spatial resolutions.
View Article and Find Full Text PDFChem Soc Rev
January 2025
Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic.
Since the debut of silicene in the experimental stage more than a decade ago, the family of two-dimensional elementary layers beyond graphene, called Xenes or transgraphenes, has rapidly expanded to include elements from groups II to VI of the periodic table. This expansion has opened pathways for the engineering of elementary monolayers that are inherently different from their bulk counterparts in terms of fundamental physical properties. Common guidelines for synthesizing Xenes can be categorized into well-defined methodological approaches.
View Article and Find Full Text PDFNat Mater
January 2025
Department of Physics, Harvard University, Cambridge, MA, USA.
Atomically thin van der Waals (vdW) films provide a material platform for the epitaxial growth of quantum heterostructures. However, unlike the remote epitaxial growth of three-dimensional bulk crystals, the growth of two-dimensional material heterostructures across atomic layers has been limited due to the weak vdW interaction. Here we report the double-sided epitaxy of vdW layered materials through atomic membranes.
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