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Semiconductor plasmonic

Samaneh Kameli, Ali Mehrizad
Recent improvements based on heterojunction nanocomposites have opened new possibilities in photocatalysis. In this research, an ultrasound assisted co-precipitation method was used to fabricate silver, zinc sulfide, and reduced graphene oxide (Ag-ZnS/rGO) nanocomposite, and characterization results indicated that 3% Ag-ZnS spherical nanoparticles are successfully embedded in rGO matrix. The potential of the Ag-ZnS/rGO, as a visible light active photocatalyst, was assessed through optimizing degradation of Tetracycline (TC) by response surface methodology...
August 14, 2018: Photochemistry and Photobiology
Michele Dipalo, Giovanni Melle, Laura Lovato, Andrea Jacassi, Francesca Santoro, Valeria Caprettini, Andrea Schirato, Alessandro Alabastri, Denis Garoli, Giulia Bruno, Francesco Tantussi, Francesco De Angelis
The ability to monitor electrogenic cells accurately plays a pivotal role in neuroscience, cardiology and cell biology. Despite pioneering research and long-lasting efforts, the existing methods for intracellular recording of action potentials on the large network scale suffer limitations that prevent their widespread use. Here, we introduce the concept of a meta-electrode, a planar porous electrode that mimics the optical and biological behaviour of three-dimensional plasmonic antennas but also preserves the ability to work as an electrode...
August 13, 2018: Nature Nanotechnology
Yuquan Zhang, Junfeng Shen, Changjun Min, Yunfeng Jin, Yuqiang Jiang, Jun Liu, Siwei Zhu, Yunlong Sheng, Anatoly V Zayats, Xiaocong Yuan
Optical trapping and manipulation of atoms, nanoparticles and biological entities is widely employed in quantum technology, biophysics and sensing. Single traps are typically achieved with linearly polarized light, while vortex beams form rotationally unstable symmetric traps. Here we demonstrate multiplexed optical traps reconfigurable with intensity and polarization of the trapping beam using intensity-dependent polarizability of nanoparticles. Nonlinearity combined with a longitudinal field of focused femtosecond vortex beams results in a stable optical force potential with multiple traps, in striking contrast to linear trapping regime...
August 8, 2018: Nano Letters
Suh-Ciuan Lim, Wen-Fu Lo, Po-Yuan Yang, Shu-Chen Lu, Anneli Joplin, Stephan Link, Wei-Shun Chang, Hsing-Yu Tuan
Synthesis of metal@semiconductor heteroepitaxial nanorods fully covered by a semiconductor shell remains challenging due to the large lattice mismatch between the two components. Here, we prepared Au@CdSe heteroepitaxial nanorods by employing pre-growth of Ag2 Se as an intermediate layer that favored the formation of a complete CdSe shell via a cation-exchange process. The optical properties of these hybrid nanostructures can be tailored by changing the shell thickness with thicker shells resulting in a redshift of the longitudinal surface plasmon resonance...
July 20, 2018: Journal of Colloid and Interface Science
Rupa Haldavnekar, Krishnan Venkatakrishnan, Bo Tan
Surface-enhanced Raman scattering (SERS)-based cancer diagnostics is an important analytical tool in early detection of cancer. Current work in SERS focuses on plasmonic nanomaterials that suffer from coagulation, selectivity, and adverse biocompatibility when used in vitro, limiting this research to stand-alone biomolecule sensing. Here we introduce a label-free, biocompatible, ZnO-based, 3D semiconductor quantum probe as a pathway for in vitro diagnosis of cancer. By reducing size of the probes to quantum scale, we observed a unique phenomenon of exponential increase in the SERS enhancement up to ~106 at nanomolar concentration...
August 3, 2018: Nature Communications
Nengjie Huo, Gerasimos Konstantatos
Conventional semiconductors such as silicon- and indium gallium arsenide (InGaAs)-based photodetectors have encountered a bottleneck in modern electronics and photonics in terms of spectral coverage, low resolution, nontransparency, nonflexibility, and complementary metal-oxide-semiconductor (CMOS) incompatibility. New emerging two-dimensional (2D) materials such as graphene, transition metal dichalcogenides (TMDs), and their hybrid systems thereof, however, can circumvent all these issues benefitting from mechanically flexibility, extraordinary electronic and optical properties, as well as wafer-scale production and integration...
July 31, 2018: Advanced Materials
Wei Wei, Xin Yan, Bing Shen, Jian Qin, Xia Zhang
A hybrid channel plasmon nanowire laser based on GaAs/AlGaAs core-shell semiconductor nanowire and silver V-groove is proposed. The laser structure has potential capability of integrating with plasmonic waveguides, using channel plasmon-polariton modes in V-groove plasmonic waveguides. Guiding and lasing properties are numerically calculated using finite elements method. From the theoretical results, the laser could support guiding mode with a smallest diameter of 40 nm. Lasing emission could happen at a relatively low threshold around 2000 cm- 1 when the diameter is larger than 140 nm...
July 31, 2018: Nanoscale Research Letters
Miao Sun, Mohammad Taha, Sumeet Walia, Madhu Bhaskaran, Sharath Sriram, William Shieh, Ranjith Rajasekharan Unnithan
A photonic switch is an integral part of optical telecommunication systems. A plasmonic bandpass filter integrated with materials exhibiting phase transition can be used as a thermally reconfigurable optical switch. This paper presents the design and demonstration of a broadband photonic switch based on an aluminium nanohole array on quartz utilising the semiconductor-to-metal phase transition of vanadium dioxide. The fabricated switch shows an operating range over 650 nm around the optical communication C, L, and U band with maximum 20%, 23% and 26% transmission difference in switching in the C band, L band, and U band, respectively...
July 23, 2018: Scientific Reports
Pedro D Ortiz, Judith Castillo-Rodriguez, Ximena Zarate, Rudy Martin-Trasanco, Mónica Benito, Ignasi Mata, Elies Molins, Eduardo Schott
Plasmonic nanoparticles, especially gold ones, have been widely employed as photosensitizers in photoelectrovoltaic or photocatalytic systems. To improve the system's performance, a greater interaction of the nanoparticles with the semiconductor, generally TiO2 , is desired. Moreover, this performance is enhanced when an efficient covering of TiO2 surface by the sensitizer is achieved. The Brust-Schiffrin-like methods are of the most employed approaches for nanoparticles synthesis. In a traditional approach, the reduction of the gold precursor is performed in the presence of a stabilizer (typically a thiol molecule) free in solution...
August 2, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Chuanping Li, Ping Wang, Haijuan Li, Minmin Wang, Jie Zhang, Guohua Qi, Yongdong Jin
Understanding and controlling the charge transfer behavior across the interface/junction in hybrid nanostructures is essential for various plasmon-enhanced catalytic reactions. The rational design of plasmonic nanostructures offers a unique capability for eliminating the daunting complexity of the electronic effect induced by interfacial interactions and maximizing the conversion efficiency of solar energy into chemical energy by surface coupling. Herein, we tactfully construct a new type of plasmon-driven photoanode based on plasmonic metal-insulator-semiconductor (PMIS) hetero-nanostructures (Au@SiO2 NP-decorated α-Fe2 O3 nanorod array), by using Fe2 O3 nanoarrays as model semiconductor structures and Au@SiO2 NPs as photosensitizers, for optimizing the photoelectrochemical (PEC) water splitting performance...
August 7, 2018: Nanoscale
Takahiro Furuki, Masashi Ota, Mitsuo Fukuda
We demonstrate a plasmonic slow light device using super focusing on a bow-tied metallic waveguide that can be fabricated using complementary metal-oxide semiconductor compatible processes. By solving the characteristic equation of a bow-tied metallic waveguide, we confirmed that the group indices increased as the waveguide width decreased and that they could attain over 11.0 in the telecommunication wavelength band. Additionally, we experimentally confirmed using an autocorrelation measurement system in which the pulse width of the bow-tied metallic waveguide was 8...
July 15, 2018: Optics Letters
Christian Schneider, Mikhail M Glazov, Tobias Korn, Sven Höfling, Bernhard Urbaszek
The optical properties of transition metal dichalcogenide monolayers are widely dominated by excitons, Coulomb-bound electron-hole pairs. These quasi-particles exhibit giant oscillator strength and give rise to narrow-band, well-pronounced optical transitions, which can be brought into resonance with electromagnetic fields in microcavities and plasmonic nanostructures. Due to the atomic thinness and robustness of the monolayers, their integration in van der Waals heterostructures provides unique opportunities for engineering strong light-matter coupling...
July 12, 2018: Nature Communications
Omidreza Daneshmandi, Rahman Sharaf, Rahim Ghayour
A new metal-semiconductor-metal photodetector (MSM-PD) based on a hybrid plasmonic and extra ordinary transmission (EOT) phenomenon is proposed. In the designed structure, we demonstrate that light transmission is improved by means of a new shape of surface nanograting and by optimizing the physical parameters of the metal. In this work the optical transfer parameters are strongly interrelated and all the parameters are optimized and the light transmission is enhanced by 55 times compared to the reference structure...
October 5, 2018: Nanotechnology
Omid Zandi, Ankit Agrawal, Alex B Shearer, Lauren C Reimnitz, Clayton J Dahlman, Corey M Staller, Delia J Milliron
Degenerately doped semiconductor nanocrystals (NCs) exhibit a localized surface plasmon resonance (LSPR) in the infrared range of the electromagnetic spectrum. Unlike metals, semiconductor NCs offer tunable LSPR characteristics enabled by doping, or via electrochemical or photochemical charging. Tuning plasmonic properties through carrier density modulation suggests potential applications in smart optoelectronics, catalysis and sensing. Here, we elucidate fundamental aspects of LSPR modulation through dynamic carrier density tuning in Sn-doped In2 O3 (Sn:In2 O3 ) NCs...
July 9, 2018: Nature Materials
Yang Liu, Maixian Liu, Deqiang Yin, Liang Qiao, Zheng Fu, Mark T Swihart
Heterogeneous copper sulfide based nanostructures have attracted intense attention based on their potential to combine the plasmonic properties of copper-deficient copper sulfides with properties of other semiconductors and metals. In general, copper sulfides are versatile platforms for production of other materials by cation incorporation and exchange processes. However, the outcomes of subsequent cation exchange (CE) or incorporation processes involving nanoheterostructure (NH) templates have not been explored...
July 17, 2018: ACS Nano
Nikhil Bhalla, Pedro Estrela
Multimodal sensing methods have a great promise in biosensing applications as they can measure independently several properties that characterise the biomolecular interaction to be detected as well as providing inherent on-chip validation of the sensing signals. This work describes the mechanisms of a concept of insulator-semiconductor field-effect devices coupled with nanoplasmonic sensing as a promising technology, which can be used for a wide range of analytical sensing applications. The developed method involves coupling of the localized surface plasmons (LSPs) within gold nanoparticles (AuNPs) and excitons within pH sensitive silicon nitride (Si3N4) nanofilms for screening inhibitors of kinase, which constitute an important class of chemotherapy drugs...
July 19, 2018: Nanoscale
Mihnea Rosu-Hamzescu, Cristina Polonschii, Sergiu Oprea, Dragos Popescu, Sorin David, Dumitru Bratu, Eugen Gheorghiu
Electro-optical measurements, i.e., optical waveguides and plasmonic based electrochemical impedance spectroscopy (P-EIS), are based on the sensitive dependence of refractive index of electro-optical sensors on surface charge density, modulated by an AC electrical field applied to the sensor surface. Recently, P-EIS has emerged as a new analytical tool that can resolve local impedance with high, optical spatial resolution, without using microelectrodes. This study describes a high speed image acquisition and processing system for electro-optical measurements, based on a high speed complementary metal-oxide semiconductor (CMOS) sensor and a field-programmable gate array (FPGA) board...
June 2018: Review of Scientific Instruments
Niko Hildebrandt, Oya Tagit
The use of nanotechnologies for the development of highly sensitive and affordable diagnostic assays has significantly improved the ability to detect and characterize multiple types of biomarkers. Semiconductor and metal nanoparticles with unique optical properties have been successfully integrated within biomarker detection schemes for the generation and enhancement of optical signals in label-based and label-free assays. Highly sensitive label-based diagnostics has been realized particularly via using quantum dots (QDs) as labeling probes...
October 1, 2018: Journal of Nanoscience and Nanotechnology
Scott Kevin Cushing, Chih-Jung Chen, Chung Li Dong, Xiang-Tian Kong, Alexander O Govorov, Ru-Shi Liu, Nianqiang Wu
For semiconductors photosensitized with organic dyes or quantum dots, transferred electrons are usually considered thermalized at the conduction band edge. This study suggests that the electrons injected from a plasmonic metal into a thin semiconductor shell can be nonthermal with energy up to the plasmon frequency. In other words, the electrons injected into the semiconductor are still hot carriers. Photomodulated X-ray absorption measurements of the Ti L2,3 edge are compared before and after excitation of the plasmon in Au@TiO2 core-shell nanoparticles...
July 24, 2018: ACS Nano
Yiwen Li, Jiaji Cheng, Jiagen Li, Xi Zhu, Tingchao He, Rui Chen, Zikang Tang
Understanding the interactions between a semiconducting nanocrystal surface and chiral anchoring molecules could resolve the mechanism of chirality induction in nanoscale and facilitate the rational design of chiral semiconducting materials for chiroptics. Now, chiral molybdenum oxide nanoparticles are presented in which chirality is transferred via a bio-to-nano approach. With facile control of the amount of chiral cysteine molecules under redox treatment, circular dichroism (CD) signals are generated in the plasmon region and metal-ligand charge-transfer band...
June 25, 2018: Angewandte Chemie
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