Nanomaterials

Editorial

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6 pages, 591 KiB

Open AccessEditorial

Dynamics and Applications of Photon-Nanostructured Systems

by Evangelia Sarantopoulou

Nanomaterials 2020, 10(9), 1741; https://doi.org/10.3390/nano10091741 - 03 Sep 2020

Viewed by 1622

Abstract

In a speedy and complicated word, only a small number of book readers have the time to dig out the hidden “gemstones” between the text lines [...] Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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Research

Jump to: Editorial, Review

12 pages, 3327 KiB

Open AccessArticle

Nanolayer Growth on 3-Dimensional Micro-Objects by Pulsed Laser Deposition

by Nikolaos A. Vainos, Eleftherios Bagiokis, Vagelis Karoutsos, Jingshan Hou, Yufeng Liu, Jun Zou, Yongzheng Fang, Konstantina Papachristopoulou, Antonella Lorusso, Anna Paola Caricato and Alessio Perrone

Nanomaterials 2021, 11(1), 35; https://doi.org/10.3390/nano11010035 - 25 Dec 2020

Cited by 2 | Viewed by 1949

Abstract

Pulsed laser deposition on 3-dimensional micro-objects of complex morphology is demonstrated by the paradigmatic growth of cellulose and polymer/Y₃Al₅O₁₂:Ce phosphor composite nanolayers. Congruent materials transfer is a result of multicomponent ablation performed by relatively low fluence (<200 [...] Read more.

Pulsed laser deposition on 3-dimensional micro-objects of complex morphology is demonstrated by the paradigmatic growth of cellulose and polymer/Y₃Al₅O₁₂:Ce phosphor composite nanolayers. Congruent materials transfer is a result of multicomponent ablation performed by relatively low fluence (<200 mJ cm⁻²) ArF excimer laser pulses (λ = 193 nm). Films grown on optical and engineering components, having a thickness from ~50 nm to more than ~300 nm, are durable, well adherent and maintain the structural and functional properties of the parent solids. The results verify the unique capabilities of deep-ultraviolet pulsed laser deposition of novel functional nanostructures on arbitrary surface morphologies and highlight its potential in future 3-dimensional nanotechnologies. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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12 pages, 2996 KiB

Open AccessArticle

Systolic Nanofabrication of Super-Resolved Photonics and Biomimetics

by Konstantina Papachristopoulou and Nikolaos A. Vainos

Nanomaterials 2020, 10(12), 2418; https://doi.org/10.3390/nano10122418 - 03 Dec 2020

Cited by 4 | Viewed by 1684

Abstract

Systolic nanofabrication is demonstrated via conformal downsizing of three-dimensional micropatterned monolithic master-casts made of extremely nanoporous aerogel and xerogel materials. The porous solid skeleton collapses by thermal treatment, generating miniaturized replicas, which preserve the original stereometric forms and incorporate minified nanoscale patterns. Paradigmatic [...] Read more.

Systolic nanofabrication is demonstrated via conformal downsizing of three-dimensional micropatterned monolithic master-casts made of extremely nanoporous aerogel and xerogel materials. The porous solid skeleton collapses by thermal treatment, generating miniaturized replicas, which preserve the original stereometric forms and incorporate minified nanoscale patterns. Paradigmatic holographic and biomimetic nanoarchitectures are conformally downsized by ~4×, yielding subwavelength surface features of less than ~150 nm. The operations demonstrate the super-resolution capabilities of this alternative concept and its potential evolution to an innovative nanotechnology of the future. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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31 pages, 8807 KiB

Open AccessFeature PaperArticle

Entropy and Random Walk Trails Water Confinement and Non-Thermal Equilibrium in Photon-Induced Nanocavities

by Vassilios Gavriil, Margarita Chatzichristidi, Dimitrios Christofilos, Gerasimos A. Kourouklis, Zoe Kollia, Evangelos Bakalis, Alkiviadis-Constantinos Cefalas and Evangelia Sarantopoulou

Nanomaterials 2020, 10(6), 1101; https://doi.org/10.3390/nano10061101 - 02 Jun 2020

Cited by 1 | Viewed by 3397

Abstract

Molecules near surfaces are regularly trapped in small cavitations. Molecular confinement, especially water confinement, shows intriguing and unexpected behavior including surface entropy adjustment; nevertheless, observations of entropic variation during molecular confinement are scarce. An experimental assessment of the correlation between surface strain and [...] Read more.

Molecules near surfaces are regularly trapped in small cavitations. Molecular confinement, especially water confinement, shows intriguing and unexpected behavior including surface entropy adjustment; nevertheless, observations of entropic variation during molecular confinement are scarce. An experimental assessment of the correlation between surface strain and entropy during molecular confinement in tiny crevices is difficult because strain variances fall in the nanometer scale. In this work, entropic variations during water confinement in 2D nano/micro cavitations were observed. Experimental results and random walk simulations of water molecules inside different size nanocavitations show that the mean escaping time of molecular water from nanocavities largely deviates from the mean collision time of water molecules near surfaces, crafted by 157 nm vacuum ultraviolet laser light on polyacrylamide matrixes. The mean escape time distribution of a few molecules indicates a non-thermal equilibrium state inside the cavity. The time differentiation inside and outside nanocavities reveals an additional state of ordered arrangements between nanocavities and molecular water ensembles of fixed molecular length near the surface. The configured number of microstates correctly counts for the experimental surface entropy deviation during molecular water confinement. The methodology has the potential to identify confined water molecules in nanocavities with life science importance. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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7 pages, 9821 KiB

Open AccessArticle

Miniaturized GaAs Nanowire Laser with a Metal Grating Reflector

by Wei Wei, Xin Yan and Xia Zhang

Nanomaterials 2020, 10(4), 680; https://doi.org/10.3390/nano10040680 - 04 Apr 2020

Cited by 5 | Viewed by 2426

Abstract

This work proposed a miniaturized nanowire laser with high end-facet reflection. The high end-facet reflection was realized by integrating an Ag grating between the nanowire and the substrate. Its propagation and reflection properties were calculated using the finite elements method. The simulation results [...] Read more.

This work proposed a miniaturized nanowire laser with high end-facet reflection. The high end-facet reflection was realized by integrating an Ag grating between the nanowire and the substrate. Its propagation and reflection properties were calculated using the finite elements method. The simulation results show that the reflectivity can be as high as 77.6% for a nanowire diameter of 200 nm and a period of 20, which is nearly three times larger than that of the nanowire without a metal grating reflector. For an equal length of nanowire with/without the metal grating reflector, the corresponding threshold gain is approximately a quarter of that of the nanowire without the metal grating reflector. Owing to the high reflection, the length of the nanowire can be reduced to 0.9 μm for the period of 5, resulting in a genuine nanolaser, composed of nanowire, with three dimensions smaller than 1 μm (the diameter is 200 nm). The proposed nanowire laser with a lowered threshold and reduced dimensions would be of great significance in on-chip information systems and networks. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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18 pages, 3191 KiB

Open AccessArticle

Porous Si-SiO₂ UV Microcavities to Modulate the Responsivity of a Broadband Photodetector

by María R. Jimenéz-Vivanco, Godofredo García, Jesús Carrillo, Francisco Morales-Morales, Antonio Coyopol, Miguel Gracia, Rafael Doti, Jocelyn Faubert and J. Eduardo Lugo

Nanomaterials 2020, 10(2), 222; https://doi.org/10.3390/nano10020222 - 28 Jan 2020

Cited by 13 | Viewed by 3376

Abstract

Porous Si-SiO₂ UV microcavities are used to modulate a broad responsivity photodetector (GVGR-T10GD) with a detection range from 300 to 510 nm. The UV microcavity filters modified the responsivity at short wavelengths, while in the visible range the filters only attenuated the [...] Read more.

Porous Si-SiO₂ UV microcavities are used to modulate a broad responsivity photodetector (GVGR-T10GD) with a detection range from 300 to 510 nm. The UV microcavity filters modified the responsivity at short wavelengths, while in the visible range the filters only attenuated the responsivity. All microcavities had a localized mode close to 360 nm in the UV-A range, and this meant that porous Si-SiO₂ filters cut off the photodetection range of the photodetector from 300 to 350 nm, where microcavities showed low transmission. In the short-wavelength range, the photons were absorbed and did not contribute to the photocurrent. Therefore, the density of recombination centers was very high, and the photodetector sensitivity with a filter was lower than the photodetector without a filter. The maximum transmission measured at the localized mode (between 356 and 364 nm) was dominant in the UV-A range and enabled the flow of high energy photons. Moreover, the filters favored light transmission with a wavelength from 390 nm to 510 nm, where photons contributed to the photocurrent. Our filters made the photodetector more selective inside the specific UV range of wavelengths. This was a novel result to the best of our knowledge. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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16 pages, 8263 KiB

Open AccessArticle

Picosecond Laser-Induced Hierarchical Periodic Near- and Deep-Subwavelength Ripples on Stainless-Steel Surfaces

by Shijie Ding, Dehua Zhu, Wei Xue, Wenwen Liu and Yu Cao

Nanomaterials 2020, 10(1), 62; https://doi.org/10.3390/nano10010062 - 26 Dec 2019

Cited by 8 | Viewed by 2990

Abstract

Ultrafast laser-induced periodic surface subwavelength ripples, categorized based on the ripple period into near-subwavelength ripples (NSRs) and deep-subwavelength ripples (DSRs), are increasingly found in the variety of materials such as metals, semiconductors and dielectrics. The fabrication of hierarchical periodic NSRs and DSRs on [...] Read more.

Ultrafast laser-induced periodic surface subwavelength ripples, categorized based on the ripple period into near-subwavelength ripples (NSRs) and deep-subwavelength ripples (DSRs), are increasingly found in the variety of materials such as metals, semiconductors and dielectrics. The fabrication of hierarchical periodic NSRs and DSRs on the same laser-irradiated area is still a challenge since the connection between the two remains a puzzle. Here we present an experimental study of linearly polarized picosecond laser-induced hierarchical periodic NSRs and DSRs on stainless-steel surfaces. While experiencing peak power density higher than a threshold value of 91.9 GW/cm², in the laser-scanned area appear the hierarchical periodic NSRs and DSRs (in particular, the DSRs are vertically located in the valley of parallel NSRs). A large area of the uniformly hierarchical periodic NSRs and DSRs, with the spatial periods 356 ± 17 nm and 58 ± 15 nm, respectively, is fabricated by a set of optimized laser-scanning parameters. A qualitative explanation based on the surface plasmon polariton (SPP) modulated periodic coulomb explosion is proposed for unified interpretation of the formation mechanism of hierarchical periodic NSRs and DSRs, which includes lattice orientation of grains as a factor at low peak power density, so that the initial DSRs formed have a clear conformance with the metallic grains. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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11 pages, 1239 KiB

Open AccessArticle

Nanopillar Diffraction Gratings by Two-Photon Lithography

by Julia Purtov, Peter Rogin, Andreas Verch, Villads Egede Johansen and René Hensel

Nanomaterials 2019, 9(10), 1495; https://doi.org/10.3390/nano9101495 - 19 Oct 2019

Cited by 29 | Viewed by 4373

Abstract

Two-dimensional photonic structures such as nanostructured pillar gratings are useful for various applications including wave coupling, diffractive optics, and security features. Two-photon lithography facilitates the generation of such nanostructured surfaces with high precision and reproducibility. In this work, we report on nanopillar diffraction [...] Read more.

Two-dimensional photonic structures such as nanostructured pillar gratings are useful for various applications including wave coupling, diffractive optics, and security features. Two-photon lithography facilitates the generation of such nanostructured surfaces with high precision and reproducibility. In this work, we report on nanopillar diffraction gratings fabricated by two-photon lithography with various laser powers close to the polymerization threshold of the photoresist. As a result, defect-free arrays of pillars with diameters down to 184 nm were fabricated. The structure sizes were analyzed by scanning electron microscopy and compared to theoretical predictions obtained from Monte Carlo simulations. The optical reflectivities of the nanopillar gratings were analyzed by optical microscopy and verified by rigorous coupled-wave simulations. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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13 pages, 4004 KiB

Open AccessArticle

Spectral Modulation of Optofluidic Coupled-Microdisk Lasers in Aqueous Media

by Zhihe Guo, Haotian Wang, Chenming Zhao, Lin Chen, Sheng Liu, Jinliang Hu, Yi Zhou and Xiang Wu

Nanomaterials 2019, 9(10), 1439; https://doi.org/10.3390/nano9101439 - 11 Oct 2019

Cited by 6 | Viewed by 2491

Abstract

We present the spectral modulation of an optofluidic microdisk device and investigate the mechanism and characteristics of the microdisk laser in aqueous media. The optofluidic microdisk device combines a solid-state dye-doped polymer microdisk with a microfluidic channel device, whose optical field can interact [...] Read more.

We present the spectral modulation of an optofluidic microdisk device and investigate the mechanism and characteristics of the microdisk laser in aqueous media. The optofluidic microdisk device combines a solid-state dye-doped polymer microdisk with a microfluidic channel device, whose optical field can interact with the aqueous media. Interesting phenomena, such as mode splitting and single-mode lasing in the laser spectrum, can be observed in two coupled microdisks under the pump laser. We modulated the spectra by changing the gap of the two coupled microdisks, the refractive indices of the aqueous media, and the position of a pump light, namely, selective pumping schemes. This optofluidic microlaser provides a method to modulate the laser spectra precisely and flexibly, which will help to further understand spectral properties of coupled microcavity laser systems and develop potential applications in photobiology and photomedicine. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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9 pages, 1802 KiB

Open AccessArticle

Lightning-Rod Effect of Plasmonic Field Enhancement on Hydrogen-Absorbing Transition Metals

by Norihiko Fukuoka and Katsuaki Tanabe

Nanomaterials 2019, 9(9), 1235; https://doi.org/10.3390/nano9091235 - 30 Aug 2019

Cited by 24 | Viewed by 4213

Abstract

The plasmonic enhancement of electromagnetic field energy density at the sharp tips of nanoparticles or nanoscale surface roughnesses of hydrogen-absorbing transition metals, Pd, Ti, and Ni, is quantitatively investigated. A large degree of energy focusing is observed for these transition metals in the [...] Read more.

The plasmonic enhancement of electromagnetic field energy density at the sharp tips of nanoparticles or nanoscale surface roughnesses of hydrogen-absorbing transition metals, Pd, Ti, and Ni, is quantitatively investigated. A large degree of energy focusing is observed for these transition metals in the microwave region, even surpassing the enhancement for noble metals according to the conditions. Pd, for instance, exhibits peak field enhancement factors of 6000 and 2 × 10⁸ in air for morphological aspect ratios of 10 and 100, respectively. Metal surfaces possibly contain such degrees of nano- or micro-scale native random roughnesses, and, therefore, the field enhancement effect may have been unknowingly produced in existing electrical and optical systems. In addition, for future devices under development, particularly in hydrogen-related applications, it is desirable to design and optimize the systems, including the choice of materials, structures, and operating conditions, by accounting for the plasmonic local energy enhancement effect around the metal surfaces. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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14 pages, 3634 KiB

Open AccessArticle

Guided Mode Resonance Sensors with Optimized Figure of Merit

by Yi Zhou, Bowen Wang, Zhihe Guo and Xiang Wu

Nanomaterials 2019, 9(6), 837; https://doi.org/10.3390/nano9060837 - 01 Jun 2019

Cited by 47 | Viewed by 6072

Abstract

The guided mode resonance (GMR) effect is widely used in biosensing due to its advantages of narrow linewidth and high efficiency. However, the optimization of a figure of merit (FOM) has not been considered for most GMR sensors. Aimed at obtaining a higher [...] Read more.

The guided mode resonance (GMR) effect is widely used in biosensing due to its advantages of narrow linewidth and high efficiency. However, the optimization of a figure of merit (FOM) has not been considered for most GMR sensors. Aimed at obtaining a higher FOM of GMR sensors, we proposed an effective design method for the optimization of FOM. Combining the analytical model and numerical simulations, the FOM of “grating–waveguide” GMR sensors for the wavelength and angular shift detection schemes were investigated systematically. In contrast with previously reported values, higher FOM values were obtained using this method. For the “waveguide–grating” GMR sensors, a linear relationship between the grating period and groove depth was obtained, which leads to excellent FOM values for both the angular and wavelength resonance. Such higher performance GMR sensors will pave the way to lower detection limits in biosensing. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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11 pages, 2237 KiB

Open AccessArticle

On-Chip Real-Time Chemical Sensors Based on Water-Immersion-Objective Pumped Whispering-Gallery-Mode Microdisk Laser

by Qijing Lu, Xiaogang Chen, Liang Fu, Shusen Xie and Xiang Wu

Nanomaterials 2019, 9(3), 479; https://doi.org/10.3390/nano9030479 - 24 Mar 2019

Cited by 22 | Viewed by 3378

Abstract

Optical whispering-gallery-mode (WGM) microresonator-based sensors with high sensitivity and low detection limit down to single unlabeled biomolecules show high potential for disease diagnosis and clinical application. However, most WGM microresonator-based sensors, which are packed in a microfluidic cell, are a “closed” sensing configuration [...] Read more.

Optical whispering-gallery-mode (WGM) microresonator-based sensors with high sensitivity and low detection limit down to single unlabeled biomolecules show high potential for disease diagnosis and clinical application. However, most WGM microresonator-based sensors, which are packed in a microfluidic cell, are a “closed” sensing configuration that prevents changing and sensing the surrounding liquid refractive index (RI) of the microresonator immediately. Here, we present an “open” sensing configuration in which the WGM microdisk laser is directly covered by a water droplet and pumped by a water-immersion-objective (WIO). This allows monitoring the chemical reaction progress in the water droplet by tracking the laser wavelength. A proof-of-concept demonstration of chemical sensor is performed by observing the process of salt dissolution in water and diffusion of two droplets with different RI. This WIO pumped sensing configuration provides a path towards an on-chip chemical sensor for studying chemical reaction kinetics in real time. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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14 pages, 3745 KiB

Open AccessArticle

High-Performance Ultraviolet Light Detection Using Nano-Scale-Fin Isolation AlGaN/GaN Heterostructures with ZnO Nanorods

by Fasihullah Khan, Waqar Khan and Sam-Dong Kim

Nanomaterials 2019, 9(3), 440; https://doi.org/10.3390/nano9030440 - 15 Mar 2019

Cited by 27 | Viewed by 4211

Abstract

Owing to their intrinsic wide bandgap properties ZnO and GaN materials are widely used for fabricating passive-type visible-blind ultraviolet (UV) photodetectors (PDs). However, most of these PDs have a very low spectral responsivity R, which is not sufficient for detecting very low-level [...] Read more.

Owing to their intrinsic wide bandgap properties ZnO and GaN materials are widely used for fabricating passive-type visible-blind ultraviolet (UV) photodetectors (PDs). However, most of these PDs have a very low spectral responsivity R, which is not sufficient for detecting very low-level UV signals. We demonstrate an active type UV PD with a ZnO nanorod (NR) structure for the floating gate of AlGaN/GaN high electron mobility transistor (HEMT), where the AlGaN/GaN epitaxial layers are isolated by the nano-scale fins (NFIs) of two different fin widths (70 and 80 nm). In the dark condition, oxygen adsorbed at the surface of the ZnO NRs generates negative gate potential. Upon UV light illumination, the negative charge on the ZnO NRs is reduced due to desorption of oxygen, and this reversible process controls the source-drain carrier transport property of HEMT based PDs. The NFI PDs of a 70 nm fin width show the highest R of a ~3.2 × 10⁷ A/W at 340 nm wavelength among the solid-state UV PDs reported to date. We also compare the performances of NFI PDs with those of conventional mesa isolation (MI, 40 × 100 µm²). NFI devices show ~100 times enhanced R and on-off current ratio than those of MI devices. Due to the volume effect of the small active region, a much faster response speed (rise-up and fall-off times of 0.21 and 1.05 s) is also obtained from the NFI PDs with a 70 nm fin width upon the UV on-off transient. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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7 pages, 2345 KiB

Open AccessArticle

Deep Subwavelength-Scale Light Focusing and Confinement in Nanohole-Structured Mesoscale Dielectric Spheres

by Yinghui Cao, Zhenyu Liu, Oleg V. Minin and Igor V. Minin

Nanomaterials 2019, 9(2), 186; https://doi.org/10.3390/nano9020186 - 01 Feb 2019

Cited by 35 | Viewed by 4062

Abstract

One of the most captivating properties of dielectric mesoscale particles is their ability to form a sub-diffraction limited-field localization region, near their shadow surfaces. However, the transverse size of the field localization region of a dielectric mesoscale particle is usually larger than λ/3. [...] Read more.

One of the most captivating properties of dielectric mesoscale particles is their ability to form a sub-diffraction limited-field localization region, near their shadow surfaces. However, the transverse size of the field localization region of a dielectric mesoscale particle is usually larger than λ/3. In this present paper, for the first time, we present numerical simulations to demonstrate that the size of the electromagnetic field that forms in the localized region of the dielectric mesoscale sphere can be significantly reduced by introducing a nanohole structure at its shadow surface, which improves the spatial resolution up to λ/40 and beyond the solid immersion diffraction limit of λ/2n. The proposed nanohole-structured microparticles can be made from common natural optical materials, such as glass, and are important for advancing the particle-lens-based super-resolution technologies, including sub-diffraction imaging, interferometry, surface fabrication, enhanced Raman scattering, nanoparticles synthesis, optical tweezer, etc. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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12 pages, 2055 KiB

Open AccessArticle

Quantum Characteristics of a Nanomechanical Resonator Coupled to a Superconducting LC Resonator in Quantum Computing Systems

by Jeong Ryeol Choi and Sanghyun Ju

Nanomaterials 2019, 9(1), 20; https://doi.org/10.3390/nano9010020 - 24 Dec 2018

Cited by 5 | Viewed by 3268

Abstract

The mechanical and quantum properties of a nanomechanical resonator can be improved by connecting it to a superconducting resonator in a way that the resonator exhibits new phenomena that are possibly available to novel quantum technologies. The quantum characteristics of a nanomechanical resonator [...] Read more.

The mechanical and quantum properties of a nanomechanical resonator can be improved by connecting it to a superconducting resonator in a way that the resonator exhibits new phenomena that are possibly available to novel quantum technologies. The quantum characteristics of a nanomechanical resonator coupled to a superconducting resonator have been investigated on the basis of rigorous quantum solutions of the combined system. The solutions of the Schrödinger equation for the coupled system have been derived using the unitary transformation approach. The analytic formula of the wave functions has been obtained by applying the adiabatic condition for time evolution of the coupling parameter. The behavior of the quantum wave functions has been analyzed for several different values of parameters. The probability densities depicted in the plane of the two resonator coordinates are distorted and rotated due to the coupling between the resonators. In addition, we have shown that there are squeezing effects in the wave packet along one of the two resonator coordinates or along both the two depending on the magnitude of several parameters, such as mass, inductance, and angular frequencies. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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Review

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24 pages, 2980 KiB

Open AccessReview

High Sensitivity Resists for EUV Lithography: A Review of Material Design Strategies and Performance Results

by Theodore Manouras and Panagiotis Argitis

Nanomaterials 2020, 10(8), 1593; https://doi.org/10.3390/nano10081593 - 14 Aug 2020

Cited by 80 | Viewed by 17405

Abstract

The need for decreasing semiconductor device critical dimensions at feature sizes below the 20 nm resolution limit has led the semiconductor industry to adopt extreme ultra violet (EUV) lithography with exposure at 13.5 nm as the main next generation lithographic technology. The broad [...] Read more.

The need for decreasing semiconductor device critical dimensions at feature sizes below the 20 nm resolution limit has led the semiconductor industry to adopt extreme ultra violet (EUV) lithography with exposure at 13.5 nm as the main next generation lithographic technology. The broad consensus on this direction has triggered a dramatic increase of interest on resist materials of high sensitivity especially designed for use in the EUV spectral region in order to meet the strict requirements needed for overcoming the source brightness issues and securing the cost efficiency of the technology. To this direction both fundamental studies on the radiation induced chemistry in this spectral area and a plethora of new ideas targeting at the design of new highly sensitive and top performing resists have been proposed. Besides the traditional areas of acid-catalyzed chemically amplified resists and the resists based on polymer backbone breaking new unconventional ideas have been proposed based on the insertion of metal compounds or compounds of other highly absorbing at EUV atoms in the resist formulations. These last developments are reviewed here. Since the effort targets to a new understanding of electron-induced chemical reactions that dominate the resist performance in this region these last developments may lead to unprecedented changes in lithographic technology but can also strongly affect other scientific areas where electron-induced chemistry plays a critical role. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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24 pages, 4511 KiB

Open AccessReview

Surface/Interface Engineering for Constructing Advanced Nanostructured Photodetectors with Improved Performance: A Brief Review

by Meng Ding, Zhen Guo, Xuehang Chen, Xiaoran Ma and Lianqun Zhou

Nanomaterials 2020, 10(2), 362; https://doi.org/10.3390/nano10020362 - 19 Feb 2020

Cited by 37 | Viewed by 4887

Abstract

Semiconductor-based photodetectors (PDs) convert light signals into electrical signals via a photon–matter interaction process, which involves surface/interface carrier generation, separation, and transportation of the photo-induced charge media in the active media, as well as the extraction of these charge carriers to external circuits [...] Read more.

Semiconductor-based photodetectors (PDs) convert light signals into electrical signals via a photon–matter interaction process, which involves surface/interface carrier generation, separation, and transportation of the photo-induced charge media in the active media, as well as the extraction of these charge carriers to external circuits of the constructed nanostructured photodetector devices. Because of the specific electronic and optoelectronic properties in the low-dimensional devices built with nanomaterial, surface/interface engineering is broadly studied with widespread research on constructing advanced devices with excellent performance. However, there still exist some challenges for the researchers to explore corresponding mechanisms in depth, and the detection sensitivity, response speed, spectral selectivity, signal-to-noise ratio, and stability are much more important factors to judge the performance of PDs. Hence, researchers have proposed several strategies, including modification of light absorption, design of novel PD heterostructures, construction of specific geometries, and adoption of specific electrode configurations to modulate the charge-carrier behaviors and improve the photoelectric performance of related PDs. Here, in this brief review, we would like to introduce and summarize the latest research on enhancing the photoelectric performance of PDs based on the designed structures by considering their surface/interface engineering and how to obtain advanced nanostructured photo-detectors with improved performance, which could be applied to design and fabricate novel low-dimensional PDs with ideal properties in the near future. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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22 pages, 6182 KiB

Open AccessReview

Inorganic Boron-Based Nanostructures: Synthesis, Optoelectronic Properties, and Prospective Applications

by Yan Tian, Zekun Guo, Tong Zhang, Haojian Lin, Zijuan Li, Jun Chen, Shaozhi Deng and Fei Liu

Nanomaterials 2019, 9(4), 538; https://doi.org/10.3390/nano9040538 - 03 Apr 2019

Cited by 35 | Viewed by 4944

Abstract

Inorganic boron-based nanostructures have great potential for field emission (FE), flexible displays, superconductors, and energy storage because of their high melting point, low density, extreme hardness, and good chemical stability. Until now, most researchers have been focused on one-dimensional (1D) boron-based nanostructures (rare-earth [...] Read more.

Inorganic boron-based nanostructures have great potential for field emission (FE), flexible displays, superconductors, and energy storage because of their high melting point, low density, extreme hardness, and good chemical stability. Until now, most researchers have been focused on one-dimensional (1D) boron-based nanostructures (rare-earth boride (REB₆) nanowires, boron nanowires, and nanotubes). Currently, two-dimensional (2D) borophene attracts most of the attention, due to its unique physical and chemical properties, which make it quite different from its corresponding bulk counterpart. Here, we offer a comprehensive review on the synthesis methods and optoelectronics properties of inorganic boron-based nanostructures, which are mainly concentrated on 1D rare-earth boride nanowires, boron monoelement nanowires, and nanotubes, as well as 2D borophene and borophane. This review paper is organized as follows. In Section I, the synthesis methods of inorganic boron-based nanostructures are systematically introduced. In Section II, we classify their optical and electrical transport properties (field emission, optical absorption, and photoconductive properties). In the last section, we evaluate the optoelectronic behaviors of the known inorganic boron-based nanostructures and propose their future applications. Full article

(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)

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