RESUMEN
The work function W of Mo(6)S(3)I(6) molecular nanowires is determined by Kelvin probe (KP) measurements, UV photoelectron spectroscopy (UPS), and cyclic voltammetry (CV). The values obtained by all three methods agree well, giving W = 4.8 ± 0.1 eV. CV measurements also give a gap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of E(g) = 1.2 ± 0.1 eV, in agreement with recent optical measurements, but in disagreement with theoretical calculations, which predict the material to be a metal. The electronic structure of Mo(6)S(3)I(6) suggests use of the material in applications such as bulk heterostructure photovoltaics and transparent electrodes and for molecular electronics devices.
RESUMEN
We report on the production and characterisation of optical microring resonators and optical channel waveguides by using fluorine-ion implantation and planar structuring in lithium niobate. We demonstrate the production of single-mode planar waveguides by low fluence fluorine-ion implantation (?? = 2.5 x10(14) ions/cm(2)) into lithium niobate wafers. The waveguides are strongly confined by the amorphous 2-microm wide optical barrier induced by the implantation process. A refractive index contrast of Deltan(o) = 0.17 at the telecom wavelength lambda = 1.5 microm has been determined between the waveguide and the barrier. Planar structuring with ridge height of up to 1.2 microm has been achieved by laser lithography masking and Ar(+) sputtering. For TE waves, the channel waveguides exhibit propagation losses lower than 8 dB/cm. First ring resonators with 80-microm radius have been fabricated by planar structuring in fluorine-ion implanted lithium niobate. The measured resonance curves show an extinction ratio of 14 dB, a free spectral range of 2.0 nm and a finesse of 4.