77 research outputs found
Decoupling Graphene from SiC(0001) via Oxidation
When epitaxial graphene layers are formed on SiC(0001), the first carbon
layer (known as the "buffer layer"), while relatively easy to synthesize, does
not have the desirable electrical properties of graphene. The conductivity is
poor due to a disruption of the graphene pi-bands by covalent bonding to the
SiC substrate. Here we show that it is possible to restore the graphene
pi-bands by inserting a thin oxide layer between the buffer layer and SiC
substrate using a low temperature, CMOS-compatible process that does not damage
the graphene layer
Probing the Thermal Deoxygenation of Graphene Oxide using High Resolution In Situ X-Ray based Spectroscopies
Despite the recent developments in Graphene Oxide due to its importance as a
host precursor of Graphene, the detailed electronic structure and its evolution
during the thermal reduction remain largely unknown, hindering its potential
applications. We show that a combination of high resolution in situ X-ray
photoemission and X-ray absorption spectroscopies offer a powerful approach to
monitor the deoxygenation process and comprehensively evaluate the electronic
structure of Graphene Oxide thin films at different stages of the thermal
reduction process. It is established that the edge plane carboxyl groups are
highly unstable, whereas carbonyl groups are more difficult to remove. The
results consistently support the formation of phenol groups through reaction of
basal plane epoxide groups with adjacent hydroxyl groups at moderate degrees of
thermal activation (~400 {\deg}C). The phenol groups are predominant over
carbonyl groups and survive even at a temperature of 1000 {\deg}C. For the
first time a drastic increase in the density of states (DOS) near the Fermi
level at 600 {\deg}C is observed, suggesting a progressive restoration of
aromatic structure in the thermally reduced graphene oxideComment: Pagona Papakonstantinou as Corresponding author, E-mail:
[email protected]
History, Commemoration, and Belief: Abraham Lincoln in American Memory, 1945-2001
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91765/1/Schuman-History_Commemoration_Belief.pd
SERTOLI CELL TUMOUR IN A TRUE HERMAPHRODITE: SUGGESTIVE EVIDENCE FOR ECTOPIC GONADOTROPHIN PRODUCTION BY THE TUMOUR. CASE REPORT
An infrared study of H8Si8O12H8Si8O12 cluster adsorption on Si(100) surfaces
Motivated by a controversy about the proper interpretation of x-ray photoelectron spectra of Si/SiO2Si/SiO2 interfaces derived from the adsorption of H8Si8O12H8Si8O12 spherosiloxane clusters on Si(100) surfaces, we have studied the adsorption geometry of the H8Si8O12H8Si8O12 clusters on deuterium-passivated and clean Si(100) surfaces by using external reflection infrared spectroscopy. Access to frequencies below 1450 cm−11450cm−1 was made possible through the use of specially prepared Si(100) samples which have a buried metallic CoSi2CoSi2 layer that acts as an internal mirror. A comparison of the infrared spectrum of the clusters on a deuterium-passivated Si(100) surface at 130 K with an infrared spectrum of the clusters in a carbon tetrachloride solution reveals that the clusters are only weakly physisorbed on the D/Si(100) surface and also provides evidence for the purity of the cluster source. We also present infrared spectra of clusters directly chemisorbed on a clean Si(100) surface and show evidence that the clusters are adsorbed on the Si(100) via attachment by one vertex. A complete assignment of the observed vibrational features, for both physisorbed and chemisorbed clusters, has been made based upon comparisons with the results obtained in ab initio calculations using gradient-corrected density functional methods. © 1998 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69818/2/JCPSA6-108-20-8680-1.pd
Age/Experience and Gender as Factors in Ethical Development of Hospitality Managers and Students
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