A current bottleneck in the thin film photovoltaic field is the fabrication of low cost electrodes. We demonstrate ultrasonically spray coated multiwalled carbon nanotube (CNT) layers as opaque and absorptive metal-free electrodes deposited at low temperatures and free of post-deposition treatment. The electrodes show sheet resistance as low as 3.4 Ω □(-1), comparable to evaporated metallic con...

We investigate the transmission properties of a metallic layer with narrow slits. We consider (time-harmonic) Maxwell's equations in the H-parallel case with a fixed incident wavelength. We denote η > 0 as the typical size of the complex structure and obtain the effective equations by letting η → 0. For metallic permittivities with negative real part, plasmonic waves can be excited on the surfa...

We propose an effective medium theory for a one-dimensional periodic array of rectangular grooves covered by a graphene sheet. Parameters of the effective medium model are given by explicit analytical expressions for both major polarizations TM and TE, and for all incident angles. In extraction of this model, we assumed single mode approximation inside the grooves. The effect of non-specular di...

We measure the temperature distribution in a biased single-layer graphene transistor using Raman scattering microscopy of the 2D-phonon band. Peak operating temperatures of 1050 K are reached in the middle of the graphene sheet at 210 kW cm(-2) of dissipated electric power. The metallic contacts act as heat sinks, but not in a dominant fashion. To explain the observed temperature profile and he...

We explore the possibility of inducing a topological insulator phase in a honeycomb lattice lacking spin-orbit interaction using a metallic (or Fermi gas) environment. The lattice and the metallic environment interact through a density-density interaction without particle tunneling, and integrating out the metallic environment produces a honeycomb sheet with in-plane oscillating long-ranged int...

Individual ribbons of graphene show orientation-dependent electronic properties of great interest, yet to ensure their perfect geometry and integrity or to assemble free ribbons into a device remains a daunting task. Here we explore, using density functional theory, an alternative possibility of "nanoroads" of pristine graphene being carved in the electrically insulating matrix of fully hydroge...

SWCNT can be conceptualized by wrapping a one-atomic-layer thick graphene into a hollow cylinder. As shown in Figure 1, the wrapping way is represented by the chiral vector (n, m), which denote the number of unit vectors along two directions in the crystal lattice of graphene sheet.1 Because of the symmetry and unique electronic structure of graphene, the structures of SWCNTs strongly affect th...

Magnetite thin films with a preferred ~111! orientation have been deposited by reactive dc magnetron sputtering from a pure Fe target onto ~100! GaAs substrates at 400 °C. The films show a clear Verwey transition in both the magnetization and sheet resistance as functions of temperature. For films deposited onto semiconducting n-type GaAs substrates, we have obtained asymmetric current–voltage ...

ZnO/Ag/ZnO nanolaminate structures were deposited by consecutive RF sputtering at room temperature.The optical transparency, sheet resistance, and figure of merit are determined in relation to the deposition time Ag film thickness ZnO top layer. An improved transmittance has been found visible spectral range structure compared multilayers without Ag. High 98% 550 nm, resistance 8 Ω/sq, (FOM) 11...

Spin-polarized density functional theory has been used to study the properties of vacancies in a graphene sheet and in single-walled carbon nanotubes (SWNTs). For graphene, we find that the vacancies are magnetic and the symmetry of the sheet is broken by the distortion of an atom next to the vacancy site. We also studied vacancies in four armchair SWNTs from (3,3) to (6,6) and six zigzag SWNTs...