LabAdviser/Technology Research/Fabrication of Hyperbolic Metamaterials using Atomic Layer Deposition: Difference between revisions
| Line 10: | Line 10: | ||
==Project Description== | ==Project Description== | ||
[[image:HMM_implementation_topology.png|400px|thumb|Figur 1. Schematics of (a) a multilayer and (b) a nanowire hyperbolic metamaterial.]] | [[image:HMM_implementation_topology.png|400px|thumb|Figur 1. Schematics of (a) a multilayer and (b) a nanowire hyperbolic metamaterial.]] | ||
This project deals with the technological development, design, and fabrication of hyperbolic metamaterials (HMMs) - one of the most unusual classes of artificial electromagnetic subwavelength structures. Electrodynamically, HMMs are described by a dielectric permittivity tensor " with components of opposite signs (e.g. <math>\varepsilon_{x}=\varepsilon_{y}<0, \varepsilon_{z}>0</math> ). HMMs possess unusually high wavevector, the optical density of states, and anisotropy, leading to a wide variety of potential applications such as broadband enhancement in the spontaneous emission for a single photon source, subwavelength imaging, sensing, thermal engineering, and steering of optical signals. HMMs have a potential to be a robust and versatile multi-functional platform for nanophotonics in the broad range of operating wavelengths from visible to THz regions and even at microwave region. Despite the proposed architecture of hyperbolic | This project deals with the technological development, design, and fabrication of hyperbolic metamaterials (HMMs) - one of the most unusual classes of artificial electromagnetic subwavelength structures. Electrodynamically, HMMs are described by a dielectric permittivity tensor " with components of opposite signs (e.g. <math>\varepsilon_{x}=\varepsilon_{y}<0, \varepsilon_{z}>0</math> ). HMMs possess unusually high wavevector, the optical density of states, and anisotropy, leading to a wide variety of potential applications such as broadband enhancement in the spontaneous emission for a single photon source, subwavelength imaging, sensing, thermal engineering, and steering of optical signals. HMMs have a potential to be a robust and versatile multi-functional platform for nanophotonics in the broad range of operating wavelengths from visible to THz regions and even at microwave region. Despite the proposed architecture of hyperbolic medium, which geometry includes simple metal/dielectric multilayers (Figure 1a) and metallic wires (Figure 1b) incorporated in dielectric host, the fabrication is still challenging, since ultrathin, continuous, pinhole free nanometer-scale coatings are desired.<br> | ||
The required high-quality thin layers have been fabricated using atomic layer deposition (ALD). It is a relatively new, cyclic, self-limiting thin film deposition technology allowing thickness control on the atomic scale. As the deposition relies on a surface reaction, conformal pinhole free films can be deposited on various substrates with advanced topology. This method has been a central theme of the project and a core fabrication technique of plasmonic and dielectric metamaterial | The required high-quality thin layers have been fabricated using atomic layer deposition (ALD). It is a relatively new, cyclic, self-limiting thin film deposition technology allowing thickness control on the atomic scale. As the deposition relies on a surface reaction, conformal pinhole free films can be deposited on various substrates with advanced topology. This method has been a central theme of the project and a core fabrication technique of plasmonic and dielectric metamaterial | ||
| Line 27: | Line 27: | ||
Finally, HMMs with two different geometries have been realized, AZO trenches and AZO pillars standing in a dielectric host (air or Si). Furthermore, it has been proposed that high aspect ratio grating structures with AZO lamellas in a silicon matrix function as a versatile platform supporting both surface and volume infrared waves. By selective etching of Si the performance of the whole structure | Finally, HMMs with two different geometries have been realized, AZO trenches and AZO pillars standing in a dielectric host (air or Si). Furthermore, it has been proposed that high aspect ratio grating structures with AZO lamellas in a silicon matrix function as a versatile platform supporting both surface and volume infrared waves. By selective etching of Si the performance of the whole structure | ||
can be reconfigured. In other words, a bi-slab HMM has been suggested, where the effective properties of the structure are controlled by the thickness of the top slab (etching depth).<br | can be reconfigured. In other words, a bi-slab HMM has been suggested, where the effective properties of the structure are controlled by the thickness of the top slab (etching depth).<br> | ||
<gallery caption="Al2O3 coatings on Si trenches" widths="500px" heights="500px" perrow="2"> | |||
image:AZO_Air_trench_SEM.png| Temperature 150 <sup>o</sup>C, 1000 cycles. | |||
image:AZO_Si_trench_SEM.png| Temperature 150 <sup>o</sup>C, 1000 cycles. | |||
</gallery> | |||
<gallery caption="" widths="500px" heights="500px" perrow="2"> | |||
image:pillars.png| Temperature 150 <sup>o</sup>C, 1000 cycles. | |||
image:tubes.png| Temperature 150 <sup>o</sup>C, 1000 cycles. | |||
</gallery> | |||
==Publications== | ==Publications== | ||