Unraveling Chemical Interactions between Titanium and Graphene for Electrical Contact Applications

The chemical interaction between Ti and graphene is of significant interest for engineering low-resistance electrical contacts. To study the interface chemistry, sequential depositions of Ti are performed on both as-received and ultrahigh-vacuum (UHV)-annealed chemical-vapor-deposition-grown graphene samples. In situ X-ray photoelectron spectroscopy (XPS) reveals no experimental evidence for the reaction of Ti with graphene at room temperature or after heating to 500 °C. The presence of the TiC chemical state is instead attributed to reactions between Ti and background gases in the UHV chamber as well as adventitious C on the surface of the graphene sample. We find that surface contamination can be substantially reduced by annealing in UHV. The deposition of Ti on graphene results in n-type doping, which manifests in core-level shifts and broadening of the graphene C 1s peak. Annealing the sample following the deposition of Ti reverses the n-type doping. The Raman spectroscopy results are in agreement wit...

[1]  R. Ruoff,et al.  Orientation‐Dependent Strain Relaxation and Chemical Functionalization of Graphene on a Cu(111) Foil , 2018, Advanced materials.

[2]  V. Panchal,et al.  Water on graphene: review of recent progress , 2018, 1804.09518.

[3]  P. Hopkins,et al.  Titanium contacts to graphene: process-induced variability in electronic and thermal transport , 2017, Nanotechnology.

[4]  A. F. Fonseca,et al.  Graphene-Titanium Interfaces from Molecular Dynamics Simulations. , 2017, ACS applied materials & interfaces.

[5]  Peter M. Litwin,et al.  (Invited) In-Vacuo Studies of Transition Metal Dichalcogenide Synthesis and Layered Material Integration , 2017 .

[6]  Wei Huang,et al.  Thermal and Mechanical Properties of Graphene–Titanium Composites Synthesized by Microwave Sintering , 2016, Acta Metallurgica Sinica (English Letters).

[7]  C. Coletti,et al.  Efficient n-type doping in epitaxial graphene through strong lateral orbital hybridization of Ti adsorbate , 2016, 1603.05862.

[8]  O. Richard,et al.  Transition metal contacts to graphene , 2015 .

[9]  F. Ducastelle,et al.  Charge transfer and electronic doping in nitrogen-doped graphene , 2015, Scientific Reports.

[10]  H. Johnson,et al.  Strain Relaxation in CVD Graphene: Wrinkling with Shear Lag. , 2015, Nano letters.

[11]  T. Pichler,et al.  X-ray photoelectron spectroscopy of graphitic carbon nanomaterials doped with heteroatoms , 2015, Beilstein journal of nanotechnology.

[12]  C. Coletti,et al.  Increasing the active surface of titanium islands on graphene by nitrogen sputtering , 2014, 1410.2741.

[13]  R. Koch,et al.  Surface-induced hybridization between graphene and titanium. , 2014, ACS nano.

[14]  L. Kavan,et al.  Interaction between graphene and copper substrate: The role of lattice orientation , 2014, 1401.8089.

[15]  T. Ohta,et al.  Rotational disorder in twisted bilayer graphene. , 2014, ACS nano.

[16]  Y. Chabal,et al.  Realistic metal-graphene contact structures. , 2014, ACS nano.

[17]  O. Seitz,et al.  Controlling the Atomic Layer Deposition of Titanium Dioxide on Silicon: Dependence on Surface Termination , 2013 .

[18]  M. C. Asensio,et al.  Is graphene on copper doped? , 2013 .

[19]  Li Qiang,et al.  Improving the internal stress and wear resistance of DLC film by low content Ti doping , 2013 .

[20]  K. Novoselov,et al.  A roadmap for graphene , 2012, Nature.

[21]  K. Novoselov,et al.  Direct experimental evidence of metal-mediated etching of suspended graphene. , 2012, ACS nano.

[22]  L. Colombo,et al.  Scaling of Al2O3 dielectric for graphene field-effect transistors , 2012 .

[23]  S. Ryu,et al.  Optical separation of mechanical strain from charge doping in graphene , 2012, Nature Communications.

[24]  Robert M. Wallace,et al.  The effect of chemical residues on the physical and electrical properties of chemical vapor deposited graphene transferred to SiO2 , 2011 .

[25]  K. McCreary,et al.  Metallic and insulating adsorbates on graphene , 2011, 1104.5289.

[26]  K. Novoselov,et al.  Metal-graphene interaction studied via atomic resolution scanning transmission electron microscopy. , 2011, Nano letters.

[27]  E. Vogel,et al.  First-principles study of metal–graphene interfaces , 2010 .

[28]  M. R. R. Tabar,et al.  The formation of atomic nanoclusters on graphene sheets , 2008, Nanotechnology.

[29]  G. Flynn,et al.  Graphene oxidation: thickness-dependent etching and strong chemical doping. , 2008, Nano letters.

[30]  J. Halbritter,et al.  On the origin of a third spectral component of C1s XPS-spectra for nc-TiC/a-C nanocomposite thin films , 2008 .

[31]  H. R. Krishnamurthy,et al.  Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor. , 2007, Nature nanotechnology.

[32]  U. Jansson,et al.  Nanocomposite nc-TiC∕a-C thin films for electrical contact applications , 2006 .

[33]  A. Kottar,et al.  Disorder-order phase transformations and electrical resistivity of nonstoichiometric titanium carbide , 1998 .

[34]  D. Briggs,et al.  Handbook of X‐ray Photoelectron Spectroscopy C. D. Wanger, W. M. Riggs, L. E. Davis, J. F. Moulder and G. E.Muilenberg Perkin‐Elmer Corp., Physical Electronics Division, Eden Prairie, Minnesota, USA, 1979. 190 pp. $195 , 1981 .

[35]  M. Jelínek,et al.  Amorphous carbon nanocomposite films doped by titanium: Surface and sub-surface composition and bonding , 2018 .