ABSTRACT
All carbon electronics based on graphene have been an elusive goal. For more than a decade, the inability to produce significant band-gaps in this material has prevented the development of graphene electronics. We demonstrate a new approach to produce semiconducting graphene that uses a submonolayer concentration of nitrogen on SiC sufficient to pin epitaxial graphene to the SiC interface as it grows. The resulting buckled graphene opens a band gap greater than 0.7 eV in the otherwise continuous metallic graphene sheet.
Subject(s)
Graphite/chemistry , Nanotechnology , Semiconductors , Electronics , Nanostructures/chemistry , Nitrogen/chemistry , Surface PropertiesABSTRACT
Past efforts to achieve selective bond scission by vibrational excitation have been thwarted by energy thermalization. Here we report resonant photodesorption of hydrogen from a Si(111) surface using tunable infrared radiation. The wavelength dependence of the desorption yield peaks at 0.26 electron volt: the energy of the Si-H vibrational stretch mode. The desorption yield is quadratic in the infrared intensity. A strong H/D isotope effect rules out thermal desorption mechanisms, and electronic effects are not applicable in this low-energy regime. A molecular mechanism accounting for the desorption event remains elusive.
ABSTRACT
A 1989 Computers in Healthcare survey finds considerably increased interest by hospital managers in bedside/point-of-care information systems, compared to results of a CIH survey in 1987. But cost-justifying these systems remains an obstacle to purchase decisions.
