Materials research plays a vital role in transforming breakthrough scientific ideas into next-generation technology. Similar to the way silicon revolutionized the microelectronics industry, the proper materials can greatly impact the field of plasmonics and metamaterials. Currently, research in plasmonics and metamaterials lacks good material building blocks in order to realize useful devices. Such devices suffer from many drawbacks arising from the undesirable properties of their material building blocks, especially metals. There are many materials, other than conventional metallic components such as gold and silver, that exhibit metallic properties and provide advantages in device performance, design flexibility, fabrication, integration, and tunability. This review explores different material classes for plasmonic and metamaterial applications, such as conventional semiconductors, transparent conducting oxides, perovskite oxides, metal nitrides, silicides, germanides, and 2D materials such as graphene. This review provides a summary of the recent developments in the search for better plasmonic materials and an outlook of further research directions.

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Alternative Plasmonic Materials: Beyond Gold and Silver

A method of fabricating a semiconductor structure including the steps of providing a silicon substrate (10) having a surface (12), forming on the surface (12) of the silicon substrate (10), by atomic layer deposition (ALD), a seed layer (20;20') characterised by a silicate material and forming, by atomic layer deposition (ALD) one or more layers of a high dielectric constant oxide (40) on the seed layer (20;20').

Method for fabricating a semiconductor structure including a metal oxide interface with silicon

In this paper a review of the more "fundamental" concerns regarding the scaling of the gate dielectric in the ultrathin regime is presented. Material issues are discussed pertaining to the integration of silicon oxynitride and oxide/nitride stacked layers and how such films might reduce or minimize boron penetration problems and address leakage current and reliability concerns. A methodology is presented to calculate device and chip lifetimes for MOS structures on the basis of data extracted from voltage- and temperature-accelerated measurements. Some integration issues regarding higher-k materials are also discussed because of their ability to solve the scaling problem. However, difficulties are involved in integrating them into a CMOS process flow.

Scaling the gate dielectric: materials, integration, and reliability

With increasing human population, sustainable energy production has become one of the most persistent and significant problems of the current century. Hydrogen is considered to be the best clean fuel for future energy requirements. As a substitute of fossil fuels, hydrogen is readily provided by an electrocatalytic hydrogen evolution reaction that splits water molecules. Conventional electrocatalysts based on noble metals are scarce and considerably expensive for large-scale hydrogen production, necessitating the search for low-cost earth abundant alternatives. In this context, transition metal nitrides have gained considerable attention as competent electrocatalytic materials for water splitting. This review presents recent advancements and progress on transition metal nitrides as efficient and cost-effective electrocatalysts for hydrogen production. After overviewing the fundamental aspects of the hydrogen evolution reaction (HER), the review discusses various synthetic strategies for developing transition metal nitrides. Discussed herein are titanium nitrides, vanadium nitrides, iron nitrides, nickel nitrides, molybdenum nitrides, tungsten nitrides, and their composite electrocatalysts employed in HER applications. Some design viewpoints for improving the electrocatalytic activity are systematically proposed. Finally, the review discusses challenges and future perspectives for the advancement of non-noble metal-based electrocatalysts.

Fundamental aspects and recent advances in transition metal nitrides as electrocatalysts for hydrogen evolution reaction: A review

Optical properties of polycrystalline and epitaxial anatase and rutile TiO2 thin films by rf magnetron sputtering

KrF pulsed excimer laser deposition was found to produce epitaxial TiN and ZrN films on Si{100} and MgO{100} substrates, respectively, with optimized laser fluence, substrate temperature and nitrogen ambient pressure. The epitaxial nature of these films was confirmed by the X-ray pole figure, and the crystallinity was evaluated from the full width at half-maximum of the X-ray ω-rocking curve and Rutherford backscattering spectroscopy. The electrical resistivities of these epitaxial TiN and ZrN films were as low as 40 µ Ω cm. The crystal orientation and impurity phase formation are discussed based on a thermodynamic consideration.

https://iopscience.iop.org/article/10.1143/JJAP.33.6308/pdf

Epitaxial Growth of Highly Crystalline and Conductive Nitride Films by Pulsed Laser Deposition

Rutile-phase TiO2 films were epitaxially grown on Si(100) substrates by oxidizing epitaxial TiN films grown by KrF pulsed excimer laser deposition. The TiO2 film was (110)-oriented and composed of two domains perpendicular to each other in the plane. The electrical resistivity at 2.5 V and the dielectric constant at 1 MHz of the film were 1.1×1010 Ω cm and 49, respectively. This film could be used as a buffer layer for the growth of epitaxial BaTiO3 film on Si. The BaTiO3 (260 nm)/TiO2 (230 nm) double-layered film showed a high dielectric constant (e r=91) and a very low leakage current of 5×10-8 A/cm2 at 10 V.

Formation and Characterization of EpitaxialTiO2andBaTiO3/TiO2Films on Si Substrate

We propose a new lithography technique using the optical near field. This technique makes use of a super-resolution near-field structure (Super-RENS) which was first proposed by us for high-density data storage. Using this structure, we have fabricated narrow grooves in a photoresist film spin-coated on a Super-RENS disk at a constant linear velocity of 6 m/s and about 400 rotations with a mercury lamp (λ=365 nm) for exposing the photoresist film and a semiconductor laser (λ=635 nm) for generating a small optical aperture. By adjusting the laser power, narrow grooves with a full-width at half-maximum (FWHM) of less than 200 nm could be fabricated in the photoresist film. Moreover, a fabrication speed 104 or 105 times greater than that with the conventional techniques using a near-field scanning optical microscope was achieved.

High-speed optical near-field photolithography by super resolution near-field structure

Pb(Zr052Ti048)O3(PZT)/CeO2 films were grown on Si(111) substrates by the pulsed laser deposition method Room-temperature (20° C) deposition of the CeO2 film on a hydrogen-terminated Si surface resulted in a sharp hetero-interface with no amorphous transition layer PZT films were grown on the CeO2 layer in {101} orientation with in-plane three directions at substrate temperatures higher than 450° C An Al/PZT(80 nm)/CeO2(24 nm)/Si structure showed a threshold voltage shift as large as 16 V (when bias voltage was 3 V) in a capacitance–voltage ( C–V ) curve due to the surface charges induced by ferroelectric polarization of the PZT film

Growth and Characterization of Ferroelectric Pb(Zr, Ti)O3 Films on Interface-Controlled CeO2(111)/Si(111) Structures

Pb(Zr0.52Ti0.48)O3 (PZT)/ SrTiO3/TiN trilayered films were grown heteroepitaxially on Si(100) substrate by pulsed laser deposition. The TiN layer was employed as a bottom electrode for the PZT capacitor and the thin SrTiO3 layer was used as a seed layer for epitaxial growth of PZT. Good crystallinity and sharp interfaces of the structure were verified by X-ray diffraction analysis and secondary ion mass spectrometry, respectively. Polarization-electric field ( P-E) curve showed a remanent polarization of 12 µ C/ cm2 and a coercive field of 130 kV/cm for a PZT film of 400 nm thickness. Leakage current at E=400 kV/cm was less than 10-7 A/cm2.

Myung Bok Lee

Papers

Epitaxial Growth of Highly Crystalline and Conductive Nitride Films by Pulsed Laser Deposition

Formation and Characterization of EpitaxialTiO2andBaTiO3/TiO2Films on Si Substrate

High-speed optical near-field photolithography by super resolution near-field structure

Growth and Characterization of Ferroelectric Pb(Zr, Ti)O3 Films on Interface-Controlled CeO2(111)/Si(111) Structures

Pulsed Laser Deposition of Epitaxial Ferroelectric Pb(Zr, Ti)O3 Films on Si(100) Substrate