Precise control of the size and gap between gold nanocubes by surface-based synthesis for high SERS performance

Soft Matter ◽  
2020 ◽  
Vol 16 (7) ◽  
pp. 1857-1865 ◽  
Author(s):  
Rana Omar ◽  
Aotmane En Naciri ◽  
Abeer Fahes ◽  
Safi Jradi ◽  
Ali Issa ◽  
...  
Keyword(s):  
Optical Properties ◽  
Spectroscopic Ellipsometry ◽  
Silicon Substrate ◽  
Spin Coating ◽  
Precise Control ◽  
Gold Precursor

Gold nanocubes with tunable size and interparticle gap were produced by altering the spin-coating speed of PMMA/gold precursor dispersion on silicon substrate. Then, their optical properties were provided by spectroscopic ellipsometry measurements.

scholarly journals Characterization of Cobalt Phthalocyanine Thin Film on Silicon Substrate Using Spectroscopic Ellipsometry

2021 ◽  
Vol 66 (7) ◽  
pp. 562
Author(s):  
K.M. Al-Adamat ◽  
H.M. El-Nasser
Keyword(s):  
Optical Properties ◽  
Spectroscopic Ellipsometry ◽  
Silicon Substrate ◽  
High Vacuum ◽  
Structural Features ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
Cobalt Phthalocyanine ◽  
Mean Square

The cobalt phthalocyanine film (CoPc) was prepared by an ultra-high vacuum system onto a silicon substrate. Structural features and optical properties of the organic semiconductor CoPc has been determined with the use of spectroscopic ellipsometry over the wavelength interval 300–1000 nm. By restricting it to 900–1000 nm the film thickness is determined, and, by the point-by-point fit, the behavior of the dielectric function is established in the entire spectral region. Thus, the optical properties are determined from spectral ellipsometric data using mathematical models based on Gaussian oscillators, which have led to an excellent fit to the experimental data with a relatively low mean square error. Cobalt phthalocyanine was treated as a uniaxial material.

STRUCTURAL, OPTICAL PROPERTIES AND PHOTOCATALYTIC ACTIVITY OF NANOCRYSTALLINE TiO2 THIN FILMS DEPOSITED BY SOL-GEL SPIN COATING

2019 ◽  
Vol 7 (1) ◽  
pp. 28
Author(s):  
KOMARAIAH DURGAM ◽  
RADHA EPPA ◽  
REDDY M. V. RAMANA ◽  
KUMAR J. SIVA ◽  
R. SAYANNA ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Photocatalytic Activity ◽  
Spin Coating ◽  
Sol Gel ◽  
Tio2 Thin Films ◽  
Nanocrystalline Tio2

Sol-gel growth of Ni doped CdS on glass substrates: effect of spin coating speed and dopant concentration

2020 ◽  
Vol 10 ◽  
Author(s):  
Atefeh Nazari Setayesh ◽  
Hassan Sedghi
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spin Coating ◽  
Optical Band Gap ◽  
Dopant Concentration ◽  
Rotation Speed ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Glass Substrates

Background: In this work, CdS thin films were synthesized by sol-gel method (spin coating technique) on glass substrates to investigate the optical behavior of the film. Methods: Different substrate spin coating speeds of 2400, 3000, 3600 rpm and different Ni dopant concentrations of 0 wt.%, 2.5 wt.%, 5 wt.%) were investigated. The optical properties of thin films such as refraction index, extinction coefficient, dielectric constant and optical band gap energy of the layers were discussed using spectroscopic ellipsometry method in the wavelength range of 300 to 900 nm. Results: It can be deduced that substrate rotation speed and dopant concentration has influenced the optical properties of thin films. By decreasing rotation speed of the substrate which results in films with more thicknesses, more optical interferences were appeared in the results. Conclusion: The samples doped with Ni comparing to pure ones have had more optical band gap energy.

scholarly journals Controlled Living Nanowire Growth: Precise Control over the Morphology and Optical Properties of AgAuAg Bimetallic Nanowires

Nano Letters ◽  
2015 ◽  
Vol 15 (8) ◽  
pp. 5427-5437 ◽  
Author(s):  
Martin Mayer ◽  
Leonardo Scarabelli ◽  
Katia March ◽  
Thomas Altantzis ◽  
Moritz Tebbe ◽  
...  
Keyword(s):  
Optical Properties ◽  
Nanowire Growth ◽  
Precise Control

scholarly journals Optical Characterization of Ultra-Thin Films of Azo-Dye-Doped Polymers Using Ellipsometry and Surface Plasmon Resonance Spectroscopy

Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 41
Author(s):  
Najat Andam ◽  
Siham Refki ◽  
Hidekazu Ishitobi ◽  
Yasushi Inouye ◽  
Zouheir Sekkat
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Spectroscopic Ellipsometry ◽  
Plasmon Resonance ◽  
Complex Refractive Index ◽  
Resonance Spectroscopy ◽  
Doped Polymers

The determination of optical constants (i.e., real and imaginary parts of the complex refractive index (nc) and thickness (d)) of ultrathin films is often required in photonics. It may be done by using, for example, surface plasmon resonance (SPR) spectroscopy combined with either profilometry or atomic force microscopy (AFM). SPR yields the optical thickness (i.e., the product of nc and d) of the film, while profilometry and AFM yield its thickness, thereby allowing for the separate determination of nc and d. In this paper, we use SPR and profilometry to determine the complex refractive index of very thin (i.e., 58 nm) films of dye-doped polymers at different dye/polymer concentrations (a feature which constitutes the originality of this work), and we compare the SPR results with those obtained by using spectroscopic ellipsometry measurements performed on the same samples. To determine the optical properties of our film samples by ellipsometry, we used, for the theoretical fits to experimental data, Bruggeman’s effective medium model for the dye/polymer, assumed as a composite material, and the Lorentz model for dye absorption. We found an excellent agreement between the results obtained by SPR and ellipsometry, confirming that SPR is appropriate for measuring the optical properties of very thin coatings at a single light frequency, given that it is simpler in operation and data analysis than spectroscopic ellipsometry.

scholarly journals Binary Self-Assembly of Nanocolloidal Arrays using Concurrent and Sequential Spin Coating Techniques

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 274
Author(s):  
Shih-Jyun Shen ◽  
Demei Lee ◽  
Yu-Chen Wu ◽  
Shih-Jung Liu
Keyword(s):  
Silicon Substrate ◽  
Self Assembly ◽  
Spin Coating ◽  
Processing Parameters ◽  
The Self ◽  
Silicon Substrates ◽  
Processing Conditions ◽  
Polystyrene Spheres ◽  
Optimal Processing ◽  
Spin Coater

This paper reports the binary colloid assembly of nanospheres using spin coating techniques. Polystyrene spheres with sizes of 900 and 100 nm were assembled on top of silicon substrates utilizing a spin coater. Two different spin coating processes, namely concurrent and sequential coatings, were employed. For the concurrent spin coating, 900 and 100 nm colloidal nanospheres of latex were first mixed and then simultaneously spin coated onto the silicon substrate. On the other hand, the sequential coating process first created a monolayer of a 900 nm nanosphere array on the silicon substrate, followed by the spin coating of another layer of a 100 nm colloidal array on top of the 900 nm array. The influence of the processing parameters, including the type of surfactant, spin speed, and spin time, on the self-assembly of the binary colloidal array were explored. The empirical outcomes show that by employing the optimal processing conditions, binary colloidal arrays can be achieved by both the concurrent and sequential spin coating processes.

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