Direct graphene growth on transitional metal with solid carbon source and its converting into graphene/transitional metal oxide heterostructure

Abstract

International audienceThe oxide/semiconductor structure is key to controlling current in electronic devices and HfO$_2$ is a common gate material in conventional electronic devices due to its favorable dielectric properties. Graphene devices also require insulating gates. We demonstrate a unique direct growth approach to obtain the bottom gate structure (graphene/HfO$_2$/n-SiC). The present approach involves transfer of graphene grown by chemical vapor deposition (CVD) on Cu to oxidized Si wafers, a complex process prone to low yield and reduced performance. Furthermore, HfO$_2$ is preferred to SiO$_2$ because of its superior properties. The proposed concept consists of the direct deposition of graphene by solid carbon molecular beam epitaxy on Hf metal coated n-type SiC, followed by oxygen intercalation to form HfO$_2$. The oxygen intercalation will then convert the underlying Hf into HfO$_2$ due to the strong affinity of Hf with oxygen. We identify the graphene/HfO 2 formation by Raman, X-ray photoelectron spectroscopy (XPS), Low energy electron diffraction (LEED), Low energy electron microscopy (LEEM) and electrical properties including Hall mobility and leakage current measurement

Hafnium Oxide/Graphene/Hafnium Oxide-Stacked Nanostructures as Resistive Switching Media

“…The Hf 4f spectra for both graphene-covered and bare HfO 2 (not shown) could be well fitted by a single spin–orbit split pair of Voigt profiles, hence indicating that the samples were chemically homogeneous, as expected for these relatively thick films . The Hf 4f 7/2 binding energy of 16.9 eV agrees with several previous studies of HfO 2 films − even if the values closer to 18 eV have also been considered . However, such a divergence of values may stem from the common but lately criticized , practice of referencing binding energies to adventitious carbon (often still the best available option), which can be circumvented using different internal references, viz., the Si 2p signal for very thin films on Si substrates, , whose use has previously visualized overcorrection using the carbon reference, , and raised reconsiderations if the surface carbon is, necessarily, in a sufficiently intimate contact to the surface, providing charge equilibrium with the oxide surface beneath.…”

Интеркалирование натрием графеновых пленок на Re(10(1)0)

“…В частности, в настоящее время одной из важных задач является создание под пленкой графена на металле диэлектрического слоя путем интеркали-рования атомов с последующим их окислением [7][8][9][10][11]. Закономерности интеркалирования графена на металлах атомами Cs, K, Na, Al, Cu, Ir, Si, Pt и др., а также молекулами C 60 представлены в нашей обобщающей работе [12], причем было показано, что именно потен-циал ионизации является важнейшей характеристикой, описывающей закономерности этого процесса.…”