Authors: B. Heim, J.P. Allain, D. Zemlyanov, C.N. Taylor, O. El-Atwani
Affilation: Purdue University, United States
Pages: 254 - 257
Keywords: graphene, graphane, lithium, XPS, UPS
The presence of defects in graphene due to thin-film processing can lead to alterations of its electronic properties. Tuning of graphene’s electronic properties could be achieved through control of thermal deposition of alkaline dopants (e.g. lithium) combined with low-energy heavy ion (Ar+ or Xe+) irradiation. In this case defect generation may be controlled enhancing tunability. Irradiation-mediated engineering of nano-structured carbon can also elicit new morphologies in carbon nanotubes or related structures. Lithium intercalation and chemical functionality in graphane (i.e. hydrogenated graphene) is unknown, whereas in polycrystalline graphite the chemical functionality of lithium with oxygen and carbon has been recently studied. Controlled irradiation and surface characterization of D-treated lithiated graphite is conducted in-situ and in real time. Using X-ray photoelectron spectroscopy fundamental differences between Li and non-Li hydrogenated graphite thin-film structures are measured. Dipole interactions induced by Li ions in the graphite matrix weakly bind deuterium. TDS (thermal desorption spectroscopy) further shows the distinct bond types, dipole and covalent that manifest in the D-treated lithiated graphite matrix. Furthermore, in-situ ultraviolet photoelectron spectroscopy (UPS) maps the electronic band structure during thermal lithium deposition and ion irradiation.
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