Title of dissertation: OPTICAL AND THERMAL PROPERTIES OF NANOPOROUS MATERIAL AND DEVICES Kyowon Kim, Doctor of Philosophy, 2015 Dissertation directed by: Professor Thomas E. Murphy Dept. of Electrical & Computer Engineering In this thesis, we investigate the optical and thermal properties of porous silicon and its applications. In first part, porous silicon’s optical properties and application ...

Temperature-dependent terahertz conductivity of tin oxide (SnO2) nanowire films was measured from 10 to 300 K using terahertz time-domain spectroscopy. The optical parameters, including the complex refractive index, optical conductivity and dielectric function, were obtained using a simple effective medium theory. The complex conductivity was fitted with the Drude–Smith model and the plasmon mo...

Optical excitation typically enhances electrical conduction and low-frequency radiation absorption in semiconductors. We, however, observe a pronounced transient decrease of conductivity in doped monolayer molybdenum disulfide (MoS(2)), a two-dimensional (2D) semiconductor, using ultrafast optical-pump terahertz-probe spectroscopy. In particular, the conductivity is reduced to only 30% of its e...

Recent Rayleigh scattering measurements show that all single-walled carbon nanotubes have a peak optical conductivity of approximately 8 e2/h, independent of radius, chiral angle, or whether the nanotube is semiconducting or metallic [D. Y. Joh et al., Nat. Nanotechnol. 6, 51 (2011)]. We show that this uniform peak conductivity is a consequence of the relativistic band structure and strength of...

We calculate the effect of the electron-phonon interaction on the electronic density of states DOS , the quasiparticle properties, and on the optical conductivity of graphene. In metals with DOS constant on the scale of phonon energies, the electron-phonon renormalizations drop out of the dressed DOS, however, due to the Dirac nature of the electron dynamics in graphene, the band DOS is linear ...

Silicon thin layers are deposited on glass substrates with the thickness of 103 nm, 147 nm and 197 nm. The layers are produced with electron gun evaporation method under ultra-high vacuum condition. The optical Reectance and the Transmittance of produced layers were measured by using spectrophotometer. The optical functions such as, real and imaginary part of refractive index, real and imaginar...

We employ dynamical mean-field theory to study the optical conductivity σ(ω) of one hole in the Holstein-t-J model. We provide an exact solution for σ(ω) in the limit of infinite connectivity. We apply our analysis to Nd2−xCexCuO4. We show that our model can explain many features of the optical conductivity in this compounds in terms of magnetic/lattice polaron formation.

A closed-form approximate expression for the optical conductivity of graphene is developed, which generates results with less than 0.8% maximum absolute error for λ>250 nm. The expression takes wavelength, temperature, chemical potential, and hopping parameter into account and provides a fast, easy, and reliable alternative to well-known methods that include singular integrals. Numerical result...

The band structure and the optical conductivity of an ABA (Bernal-type) stacked graphene trilayer are calculated. It is shown that, under appropriate doping, a strong resonant peak develops in the optical conductivity, located at the frequency corresponding to approximately 1.4 times the interlayer hopping energy and caused by the 'nesting' of two nearly parabolic bands in the electronic spectr...