AVS 61st International Symposium & Exhibition
    Materials Characterization in the Semiconductor Industry Focus Topic Tuesday Sessions
       Session MC-TuP

Paper MC-TuP8
Modification of Density of States in Iron Chloride Intercalated Epitaxial Graphene with Electric Bias

Tuesday, November 11, 2014, 6:30 pm, Room Hall D

Session: Poster Session for all areas of Materials Characterization in the Semiconductor Industry
Presenter: Taurean Groover, Clark Atlanta University
Authors: T. Groover, Clark Atlanta University
M.D. Williams, Clark Atlanta University
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Graphene, an atomic thick layer of carbon in a hexagonal lattice, has received a large amount of attention from researchers across many different scientific disciplines. Within the condensed matter physics community it is fairly well agreed that the electronic, optical, as well as structural properties of graphene are poised to revolutionize the semiconductor industry. This unique collection of properties proves promising but there are some obstacles that need to be addressed before these properties can be fully exploited. Graphene is a semimetal, which means that the conduction and valence bands touch at the Dirac point leaving no band gap to be utilized in semiconductor and optoelectronic devices. In this work we seek to investigate the electronic characteristics of epitaxial graphene, stage one and stage three ferric(III) chloride intercalated epitaxial graphene. We investigate the opening of a band gap in graphene through intercalation and in conjunction with the application of an appropriate electrical bias normal to the sample surface. Through theoretical calculations, we show that the electrical bias normal to the surface not only tunes the carrier concentration but also has the ability to switch the majority carriers from electrons to holes. The Walt de Heer Confinement Controlled Sublimation method was employed for the production of the epitaxial graphene samples and the two zone vapor transport method was employed for the intercalation of the samples. With the Confinement Controlled Sublimation growth method used, graphene is grown on SiC substrates which make these materials uniquely suited for a smooth integration into existing silicon based electronics. We observe, compare, and interpret the alteration of the density of states as well as the work functions of these samples upon the application of the electric field normal to the sample surface. Analyzing the band structure of these samples, we witness a change of the band structure from that of the AB stacking configuration to that of the decoupled AA stacking configuration. In conjunction with Raman spectroscopy, this confirms the electronic decoupling of graphene layers. Auger spectroscopy was employed to investigate the chemical environment of the near surface region of the samples and may be a viable method for stage number determination in intercalated materials. When intercalated with FeCl3, the optical transparency of the sample is conserved and the resistivity drops tremendously which makes this material, in particular, uniquely suited for the production of transparent electrodes that can be utilized to improve the performance of Li-Ion batteries.