Characterization of the structure of porous silver films by optical measurements in the near infrared

1986 ◽  
Vol 166 (1) ◽  
pp. L126-L130
Author(s):  
H.-U. Finzel ◽  
P. Wissmann ◽  
E. Wittmann
Keyword(s):  
Near Infrared ◽  
Optical Measurements ◽  
Silver Films ◽  
Porous Silver

scholarly journals Optical Characterization of Porous Sputtered Silver Thin Films

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Olivier Carton ◽  
Jaouad Ghaymouni ◽  
Michaël Lejeune ◽  
Andreas Zeinert
Keyword(s):  
Optical Properties ◽  
Optical Characterization ◽  
Optical Data ◽  
Plasma Parameters ◽  
Silver Films ◽  
Physical Measurements ◽  
Silver Thin Films ◽  
Porous Silver ◽  
Effective Medium Models

The optical properties of various porous silver films, grown with a commercial DC sputter coater, were investigated and compared for different plasma parameters. Effective Drude models were successfully used for those films whose spectra did not show particular resonance peaks. For the other films, neither an effective Drude model nor effective medium models (Maxwell Garnett, Bruggeman, and Looyenga) can describe the optical properties. It turns out that a more general approach like the Bergman representation describes the optical data of these films accurately adopting porosity values consistent with physical measurements.

scholarly journals Integrable Near-Infrared Photodetectors Based on Hybrid Erbium/Silicon Junctions

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3755 ◽  
Author(s):  
Mariano Gioffré ◽  
Giuseppe Coppola ◽  
Mario Iodice ◽  
Maurizio Casalino
Keyword(s):  
Silicon Substrate ◽  
Room Temperature ◽  
Reverse Bias ◽  
Near Infrared ◽  
Optical Measurements ◽  
Device Performance ◽  
Light Sources ◽  
Monolithically Integrated ◽  
Fabrication And Characterization

This paper presents the design, fabrication, and characterization of Schottky erbium/silicon photodetectors working at 1.55 µm. These erbium/silicon junctions are carefully characterized using both electric and optical measurements at room temperature. A Schottky barrier ΦB of ~673 meV is extrapolated; the photodetectors show external responsivity of 0.55 mA/W at room temperature under an applied reverse bias of 8 V. In addition, the device performance is discussed in terms of normalized noise and noise-equivalent power. The proposed devices will pave the way towards the development of Er-based photodetectors and light sources to be monolithically integrated in the same silicon substrate, and both operating at 1.55 µm.

scholarly journals Porous silver-coated pNIPAM-co-AAc hydrogel nanocapsules

2019 ◽  
Vol 10 ◽  
pp. 1973-1982 ◽  
Author(s):  
William W Bryan ◽  
Riddhiman Medhi ◽  
Maria D Marquez ◽  
Supparesk Rittikulsittichai ◽  
Michael Tran ◽  
...  
Keyword(s):  
Near Infrared ◽  
Localized Surface Plasmon ◽  
Nir Light ◽  
Photothermal Heating ◽  
Vis Spectroscopy ◽  
New Type ◽  
Pass Through ◽  
Porous Silver ◽  
Silver Shell

This paper describes the preparation and characterization of a new type of core–shell nanoparticle in which the structure consists of a hydrogel core encapsulated within a porous silver shell. The thermo-responsive hydrogel cores were prepared by surfactant-free emulsion polymerization of a selected mixture of N-isopropylacrylamide (NIPAM) and acrylic acid (AAc). The hydrogel cores were then encased within either a porous or complete silver shell for which the localized surface plasmon resonance (LSPR) extends from visible to near-infrared (NIR) wavelengths (i.e., λmax varies from 550 to 1050 nm, depending on the porosity), allowing for reversible contraction and swelling of the hydrogel via photothermal heating of the surrounding silver shell. Given that NIR light can pass through tissue, and the silver shell is porous, this system can serve as a platform for the smart delivery of payloads stored within the hydrogel core. The morphology and composition of the composite nanoparticles were characterized by SEM, TEM, and FTIR, respectively. UV–vis spectroscopy was used to characterize the optical properties.

scholarly journals Integrable Near-Infrared Photodetectors Based on Hybrid Erbium/Silicon Junctions

2018 ◽  
Author(s):  
Mariano Gioffrè ◽  
Giuseppe Coppola ◽  
Mario Iodice ◽  
Maurizio Casalino
Keyword(s):  
Silicon Substrate ◽  
Room Temperature ◽  
Reverse Bias ◽  
Near Infrared ◽  
Optical Measurements ◽  
Device Performance ◽  
Light Sources ◽  
Monolithically Integrated ◽  
Fabrication And Characterization

This paper presents the design, fabrication and characterization of Schottky erbium/silicon photodetectors working at 1.55 µm. These erbium/silicon junctions are carefully characterized using both electric and optical measurements at room temperature. A Schottky barrier ΦB of ~673 meV is extrapolated; the photodetectors show external responsivity of 0.55 mA/W at room temperature under a 8 V of reverse bias applied. In addition, the device performance is discussed in terms of normalized noise and noise equivalent power. To the best of our knowledge, these are the first Er/Si photodetectors designed for operation in free space at 1.55 µm. The proposed devices will pave the way towards development of Er-based photodetectors and light sources to be monolithically integrated in the same silicon substrate and both operating at 1.55 µm.

Optical Characterization of Heavily Carbon Doped GaAs

1991 ◽  
Vol 240 ◽  
Author(s):  
Lei Wang ◽  
N. M. Haegel
Keyword(s):  
Optical Absorption ◽  
Near Infrared ◽  
Infrared Region ◽  
Optical Measurements ◽  
Photoluminescence Excitation ◽  
Carbon Doped ◽  
Gaas Substrates ◽  
Metal Organic ◽  
Band Gap Narrowing

ABSTRACTOptical measurements have been performed on heavily carbon doped GaAs layers grown on semi-insulating GaAs substrates by MOMBE (metal-organic molecule beam epitaxy). Photoluminescence excitation (PLE) spectroscopy was used to measure the onsets of optical absorption in these GaAs:C epilayers. It was found that in samples with free carrier concentrations of 6.2×1019, 1.6×1020, and 4.1×1020cm−3, optical absorption begins at 1.40, 1.52, and 1.53 ev, respectively. Combined with the band gap narrowing data from photoluminescence (PL) spectra, we estimated Fermi level locations relative to the top of the valence band. We also measured reflectance in the near infrared region and estimated the effective mass of free holes using a classical two-oscillator model.

TEM characterization of proton-exchanged LiNbO3 optical waveguides

1986 ◽  
Vol 44 ◽  
pp. 480-481
Author(s):  
W. E. Lee
Keyword(s):  
Refractive Index ◽  
Benzoic Acid ◽  
Optical Waveguides ◽  
Total Internal Reflection ◽  
Index Of Refraction ◽  
Optical Measurements ◽  
Lithium Ions ◽  
Wide Channel ◽  
Tem Characterization

An optical waveguide consists of a several-micron wide channel with a slightly different index of refraction than the host substrate; light can be trapped in the channel by total internal reflection.Optical waveguides can be formed from single-crystal LiNbO3 using the proton exhange technique. In this technique, polished specimens are masked with polycrystal1ine chromium in such a way as to leave 3-13 μm wide channels. These are held in benzoic acid at 249°C for 5 minutes allowing protons to exchange for lithium ions within the channels causing an increase in the refractive index of the channel and creating the waveguide. Unfortunately, optical measurements often reveal a loss in waveguiding ability up to several weeks after exchange.

Highly Fluorescent Au25-xAgx Nanoclusters Protected with Poly(ethylene glycol) - and Zwitterion-Modified Thiolate Ligands

2018 ◽  
Author(s):  
Dinesh Mishra ◽  
Sisi Wang ◽  
Zhicheng Jin ◽  
Eric Lochner ◽  
Hedi Mattoussi
Keyword(s):  
Quantum Yield ◽  
Near Infrared ◽  
Small Diameter ◽  
Binding Energies ◽  
Thiolate Ligands ◽  
Nir Emission ◽  
Thiolate Complexes ◽  
Long Lifetime ◽  
Poly Ethylene

<p>We describe the growth and characterization of highly fluorescing, near-infrared-emitting nanoclusters made of bimetallic Au<sub>25-x</sub>Ag<sub>x</sub> cores, prepared using various monothiol-appended hydrophobic and hydrophilic ligands. The reaction uses well-defined triphenylphosphine-protected Au<sub>11</sub> clusters (as precursors), which are reacted with Ag(I)-thiolate complexes. The prepared nanoclusters are small (diameter < 2nm, as characterized by TEM) with emission peak at 760 nm and long lifetime (~12 µs). The quantum yield measured for these materials was 0.3 - 0.4 depending on the ligand. XPS measurements show the presence of both metal atoms in the core, with measured binding energies that agree with reported values for nanocluster materials. The NIR emission combined with high quantum yield, small size and ease of surface functionalization afforded by the coating, make these materials suitable to implement investigations that address fundamental questions and potentially useful for biological sensing and imaging applications.<br></p>

Sign in / Sign up

Export Citation Format

Share Document