LabAdviser/Technology Research/Fabrication of Hyperbolic Metamaterials using Atomic Layer Deposition: Difference between revisions
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[[image:Evgeniys project description.jpg|400px|thumb|Figur 1 Schematics of (a) a multilayer and (b) a nanowire hyperbolic metamaterial.]] | [[image:Evgeniys project description.jpg|400px|thumb|Figur 1 Schematics of (a) a multilayer and (b) a nanowire hyperbolic metamaterial.]] | ||
Recent years have shown an explosive interest in the physics of hyperbolic metamaterials (HMMs). Electrodynamically HMMs are described by a dielectric permittivity tensor (ε) with components of opposite signs (e.g. εx=εy<0, εz>0). In such media the unusual hyperbolic dispersion relation supports propagating waves with anomalously large wave vectors. This and related phenomena give rise to a multitude of exotic physical effects and promising applications. Examples include broadband spontaneous emission enhancement, far-field subwavelength imaging (so-called hyperlensing) and anomalous heat transfer capabilities. | Recent years have shown an explosive interest in the physics of hyperbolic metamaterials (HMMs). Electrodynamically HMMs are described by a dielectric permittivity tensor (ε) with components of opposite signs (e.g. εx=εy<0, εz>0). In such media the unusual hyperbolic dispersion relation supports propagating waves with anomalously large wave vectors. This and related phenomena give rise to a multitude of exotic physical effects and promising applications. Examples include broadband spontaneous emission enhancement, far-field subwavelength imaging (so-called hyperlensing) and anomalous heat transfer capabilities. | ||
From the fabrication standpoint, HMMs turn out to be deceptively simple: a typical geometry consists of a repeated basic metal-dielectric bilayer stack or a lattice of metallic nanowires embedded in a dielecric matrix. However, for the salient HMM properties to be pronounced, ultrathin, nanometer-scale thicknesses are required. | From the fabrication standpoint, HMMs turn out to be deceptively simple: a typical geometry consists of a repeated basic metal-dielectric bilayer stack or a lattice of metallic nanowires embedded in a dielecric matrix. However, for the salient HMM properties to be pronounced, ultrathin, nanometer-scale thicknesses are required.<br> | ||
The required high-quality ultrathin layers (around 10 nm) can be fabricated using atomic layer deposition (ALD). ALD is a cyclic self-limiting thin film deposition technology allowing molecule level thickness control. As the deposition relies on a surface reaction, conformal pinhole free films can be deposited. | The required high-quality ultrathin layers (around 10 nm) can be fabricated using atomic layer deposition (ALD). ALD is a cyclic self-limiting thin film deposition technology allowing molecule level thickness control. As the deposition relies on a surface reaction, conformal pinhole free films can be deposited.<br> | ||
The main challenge of implementation of ALD processing for HMM fabrication is the requirement for depositing alternating layers of metals (Ag, Cu, W) and dielectric spacers (alumina, titania, silica) . Required thicknesses are in the range 5-15 nm for metals and 10-20 nm for dielectrics (oxides).<br clear="all" /> | The main challenge of implementation of ALD processing for HMM fabrication is the requirement for depositing alternating layers of metals (Ag, Cu, W) and dielectric spacers (alumina, titania, silica) . Required thicknesses are in the range 5-15 nm for metals and 10-20 nm for dielectrics (oxides).<br clear="all" /> | ||