Optical and electrical properties of nanostructured metallic electrical contacts

Abstract

We study the optical and electrical properties of silver films with a graded thickness obtained through metallic evaporation in vacuum on a tilted substrate to evaluate their use as semitransparent electrical contacts. We measure their ellipsometric coefficients, optical transmissions and electrical conductivity for different widths, and we employ an efficient recursive method to calculate their macroscopic dielectric function, their optical properties and their microscopic electric fields. The topology of very thin films corresponds to disconnected islands, while very wide films are simply connected. For intermediate widths the film becomes semicontinuous, multiply connected, and its microscopic electric field develops hotspots at optical resonances which appear near the percolation threshold of the conducting phase, yielding large ohmic losses that increase the absorptance above that of a corresponding homogeneous film. Optimizing the thickness of the film to maximize its transmittance above the percolation threshold of the conductive phase we obtained a film with transmittance T = 0.41 and a sheet resistance R max ≈ 2.7Ω. We also analyze the observed emission frequency shift of porous silicon electroluminescent devices when Ag films are used as solid electrical contacts in replacement of electrolytic ones.

Evaluation of anticorrosive behaviour of ZnO nanotetra-pods on a AZ91-grade Mg alloy

“…In recent years, semiconductors with one-dimensional (1D) nanostructures, such as rods, wires, belts and tubes have received attention due to their distinctive properties for applications in life-sciences and electronics [1][2][3][4]. It is known that 1D nanostructure is useful for investigations of electrical, thermal and mechanical properties, dimensionality and quantum confinement [5]. They play a significant role as both functional and structural units in the manufacture of microelectronic, electronic and electrochemical devices [6].…”

Two-dimensional plasmons in the random impedance network model of disordered thin film nanocomposites

“…We would also mention some modern papers that study plasmon resonances in disordered systems via full-wave numerical simulations [53][54][55]. Such an approach requires significant computational resources with respect to impedance network models and thus does not allow studying large-scale properties of resonances in systems near the percolation threshold.…”

Recursive Calculation of the Optical Response of Multicomponent Metamaterials

“…[26][27][28] The method has been used to study extraordinary transmission through perforated metallic slabs, [25] to calculate plasmonic properties of odd-shaped metallic inclusions, [29] to study enhanced birrefrigency and dichroism in anisotropic metamaterials, [30] for the design and optimization of optical devices to control the absorption [31] and polarization of light, [32] and to optimize electrical and optical properties of semitransparent contacts. [33] The method has also been generalized to account for retardation, yielding a nonlocal macroscopic response from which the complete band structure of photonic crystals may be obtained [34] and from which magnetic properties may be extracted. [35] Also, there has been surged interest in the nonlinear properties of metamaterials [36,37] and metasurfaces.…”

“…A very efficient scheme for the calculation of the optical properties of metamaterials has been developed for binary metamaterials by exploiting an analogy between the macroscopic dielectric tensor and the projected Green's function corresponding to a Hermitian Hamiltonian [25] which may be obtained through Haydock's recursive pro-cedure [26,27,28]. The method has been used to study extraordinary transmission through perforated metallic slabs [25], to calculate plasmonic properties of odd shaped metallic inclusions [29], to study enhanced birrefrigency and dichroism in anisotropic metamaterials [30], for the design and optimization of optical devices to control the absorption [31] and polarization of light [32], and to optimize electrical and optical properties of semitransparent contacts [33]. The method has also been generalized to account for retardation, yielding a non-local macroscopic response from which the complete band structure of photonic crystals may be obtained [34] and from which magnetic properties may be extracted [35].…”