title: Controlled switching of optical emission energies in semiconducting single-walled carbon nanotubes.
abstract: We present scanning photoluminescence (PL) microscopy of freely suspended single-walled carbon nanotubes grown by chemically assisted vapor deposition (CVD) across micron-sized open apertures. Scans of the PL emission versus excitation position show unusual "holes"having subwavelength spatial features associated with abrupt blue shifts of the emission energy. By varying the excitation polarization, energy, intensity, and position, we demonstrate that optical switching in some nanotubes is controllable in a highly nonlinear manner by adjusting the nonequilibrium carrier density in the nanotube. Technologically important attributes include large spectral contrast between on/off states at room temperature, a dramatic response to small changes in light intensity near threshold, and the possibility that electrical charge injection could also be used to control emission energies.
authors.affiliation: Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: Milkie
authors.forename: C
authors.initials: C
authors.lastname: Staii
authors.forename: S
authors.initials: S
authors.lastname: Paulson
authors.forename: E
authors.initials: E
authors.lastname: Hindman
authors.forename: A T
authors.initials: AT
authors.lastname: Johnson
authors.forename: J M
authors.initials: JM
authors.lastname: Kikkawa
mesh_terms: D003460:Crystallization; D004583:Electrons; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D016011:Normal Distribution; D012666:Semiconductors; D012825:Silicon / Q000737:chemistry; D013053:Spectrophotometry; D013696:Temperature
chemical_list: D037742:Nanotubes, Carbon; D009584:Nitrogen; D012825:Silicon