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Journal articles
Band alignments in Fe/graphene/Si(001) junctions studied by x-ray photoemission spectroscopy
Abstract : The control of tunnel contact resistance is of primary importance for semiconductor-based spintronic devices. This control is hardly achieved with conventional oxide-based tunnel barriers due to deposition-induced interface states. Manipulation of single 2D atomic crystals (such as graphene sheets) weakly interacting with their substrate might represent an alternative and efficient way to design new heterostructures for a variety of different purposes including spin injection into semiconductors. In the present paper, we study by x-ray photoemission spectroscopy the band alignments and interface chemistry of iron-graphene-hydrogenated passivated silicon (001) surfaces for a low and a high n-doping concentration. We find that the hydrogen passivation of the Si(001) surface remains efficient even with a graphene sheet on the Si(001) surface. For both doping concentrations, the semiconductor is close to flat-band conditions which indicates that the Fermi level is unpinned on the semiconductor side of the Graphene/Si(001):H interface. When iron is deposited on the graphene/Si(001):H structures, the Schottky barrier height remains mainly unaffected by the metallic overlayer with a very low barrier height for electrons, a sought-after property in semiconductor based spintronic devices. Finally, we demonstrate that the graphene layer intercalated between the metal and semiconductor also serves as a protection against iron-silicide formation even at elevated temperatures preventing from the formation of a Si-based magnetic dead layer. © 2016 Author(s).
Keywords :
Schottky barrier heights
Magnetic dead layers
Interface chemistry
Doping concentration
Substrates
Silicon
Silicides
Semiconductor doping
Semiconductor devices
Semiconducting silicon
Elevated temperature
Hydrogen passivation
Heterojunctions
Interface states
Iron
Magnetoelectronics
Passivation
Photoelectron spectroscopy
Schottky barrier diodes
Spintronic device
X ray photoemission spectroscopy
Graphene
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01372806
Contributor : Laurent Jonchère <>
Submitted on : Tuesday, September 27, 2016 - 4:30:52 PM
Last modification on : Tuesday, January 12, 2021 - 4:41:31 PM
Contributor : Laurent Jonchère <>
Submitted on : Tuesday, September 27, 2016 - 4:30:52 PM
Last modification on : Tuesday, January 12, 2021 - 4:41:31 PM