1. X-Ray Photoelectron Spectroscopy of MgO on Graphene
David Nacouzi :: Jack Rowe,
Department of Physics ::NC State University
Background
Results
Today’s FETs (field effect transistors) are Si & SiO2 based
transistors, however a switch to FETs with graphene
(instead of Si) conducting channels would prove faster,
and more durable. The only problem is, a good oxide
is key to FET advancement.
The Graphene used in the experiment was
produced by the thermal annealing of SiC
crystals followed by the evaporation of surface
Si atoms, leaving only Carbon behind. The
MgO on the otherhand, was deposited onto the
remaining Graphene by laser evaporation.
Survey Scan of MgO on Graphene
Detailed Scan of Carbon signal
MOSFET
Objective
Detailed Scan of Oxygen signal
Gain proficiency in operating X-Ray Photoelectric Spectroscopy machinery.
Discussion
Strong Oxygen and Carbon signals were obtained from the XPS data.
The strong Carbon signals were a good sign that the oxide layer on Graphene was thin enough to allow detection of the underlying Carbon lattice.
The chemical properties of MgO tell us that it is not very reactive, meaning it isn’t easily reduced: a good result for an FET oxide since it will be stable.
Methods
XPS was used to analyze the surface chemistry of the graphene based oxide MgO.
A Riber chamber emitted Mg-K α x-rays onto the oxide surface.
The Riber software used the principles of Energy Conservation to analyze the kinetic energy of the excited atom’s ejected electron.
Both survey & detailed scans were taken to assure accurate measurements.
Next Steps
Although the MgO sample proved to be a thin enough oxide for proper Graphene conduction, there are many different oxide samples left to be analyzed in the hope of finding the thinnest combination.
Analyze different oxides as potential candidates for high-efficiency dielectrics in FETs.
Acknowledgements
:: Dr. Rowe for continual guidance with this project.
:: The NCSU Department of Physics for their financial support.