Studies of the Dielectric Constant of Thin Film Bismuth Nanowire Samples Using Optical Reectometry

2001 ◽  
Vol 635 ◽  
Author(s):  
M. R. Blacka ◽  
Y.-M. Lin ◽  
S. B. Cronin ◽  
O. Rabin ◽  
M. P adi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Energy Range ◽  
Dielectric Function ◽  
Composite System ◽  
Incident Light ◽  
Light Polarization ◽  
Alumina Template ◽  
Medium Theory ◽  
Bismuth Nanowires ◽  
Amorphous Alumina

AbstractArrays of 10 to 120 nm diameter single crystalline bismuth nanowires havebeen formed inside amorphous alumina templates. ince bismuth has a small e ective mass compared to other materials, signi cant quantum mechanical con nement is expected to occur in wires with diameter less than 50nm. he subbands formed b yquantum con nement cause in teresting modi cations to the dielectric function of bismuth. his study measures the dielectric function of bismuth nanowires in an energy range where the e ects of quantum con nement are predicted (0.05 to 0.5e). Using F ourier transforminfrared re ectometry, the dielectric constant as a function of energy is obtained for the alumina/bismuth composite system. E ective medium theory is used to subtract the e ect of the alumina template from the measurement of the composite material, thus yielding the dielectric function of bismuth nanowires. A strong absorption peak is observed at ∼1000cm−1 in the frequency dependent dielectric function in the photon energy range measured. he dependence of the frequency and intensity of this oscillator on incident light polarization and wire diameter are reviewed. n addition, the dependence of the optical absorption on antimony and tellurium doping of the nanowires are reported.

Measuring the Dielectric Properties of Nanostructures using Optical Reflection and Transmission: Bismuth Nanowires in Porous Alumina

1999 ◽  
Vol 581 ◽  
Author(s):  
M. R. Black ◽  
Y. M. Lin ◽  
M. S. Dresselhaus ◽  
M. Tachibama ◽  
S. Fang ◽  
...  
Keyword(s):  
Dielectric Function ◽  
Filling Factor ◽  
Effective Medium Theory ◽  
Porous Alumina ◽  
Reflection And Transmission ◽  
Medium Theory ◽  
Porous Alumina Template ◽  
Theoretical Predictions ◽  
Bismuth Nanowires ◽  
Transmission Measurements

ABSTRACTThis paper develops a method to deduce the dielectric function of nanostructures smaller than the chosen wavelength of light. It modifies the Maxwell - Garnett Effective Medium Theory equations to calculate the dielectric function of a metal embedded inside a dielectric. Specifically, reflection and transmission measurements of an array of bismuth nanowires in an anodized porous alumina template are used to calculate the frequency - dependent di-electric function of the nanowires. The spectra are taken using Fourier transform infrared spectroscopy covering the 500 to 4000 cm−1 frequency range. These data are used to determine the real and imaginary parts of the dielectric function of the composite materials. Next, the percentage of the total volume occupied by either Bi or air in the porous alumina (the “filling factor”) was found by scanning electron microscopy. The modified Maxwell-Garnett (M-G) equations specify how to use the filling factor and the dielectric function of the composite material to calculate the dielectric function of the alumina. Finally, the modified M-G equations are used a second time to calculate the dielectric function of Bi nanowires using the dielectric function of alumina, the dielectric function of the filled template, and the filling factor. The resulting dielectric function of Bi nanowires is then compared to theoretical predictions.

Optical properties of pure and TM-doped single-walled ZnO nanotubes (8,0) (TM = V and Co) by first principles calculations

2016 ◽  
Vol 30 (01) ◽  
pp. 1550255 ◽  
Author(s):  
R. Taghavi Mendi ◽  
M. Majidiyan Sarmazdeh ◽  
A. Boochani ◽  
S. M. Elahi ◽  
S. Naderi
Keyword(s):  
Dielectric Constant ◽  
Optical Properties ◽  
Energy Range ◽  
Dielectric Function ◽  
Optical Conductivity ◽  
Optical Transitions ◽  
Optical Reflectivity ◽  
Zno Nanotubes ◽  
Low Energies ◽  
Co Doped

In this paper, some optical properties of pure and transition metal-doped (TM = Co and V) single-walled ZnO nanotubes (8,0) (SWZnONT(8,0)) such as, real and imaginary parts of the dielectric function, optical conductivity, refractive index and optical reflectivity, were investigated. The calculations have been performed within framework of the density functional theory (DFT) using the full potential linearized augmented plane wave (FP-LAPW) and the generalized gradient approximation (GGA). The results show that, optical properties of SWZnONT(8,0) are anisotropic, especially at low energies and this anisotropy at low energies increases with doping of V in SWZnONT(8,0) while the Co-doped SWZnONT(8,0) behaves like pure SWZnONT(8,0). Doping of ZnO nanotubes has a significant impact on the value of the dielectric constant, so that due to the presence of V atom, the dielectric constant is increased up to three times. Study of the imaginary part of the dielectric function and optical conductivity showed that the important energy range for absorption processes and optical transitions is low energy range to 15 eV. The optical transitions have been studied based on band structure and density of states. The results of the optical reflectivity showed that these nanotubes are transparent in a wide energy ranges which provide them for using in transparent coatings. In addition, due to the reported magnetic properties for V- and Co-doped ZnO nanotubes, these nanotubes are suitable for using in spintronics and magneto-optic devices.

scholarly journals Characterization of Volume Gratings Based on Distributed Dielectric Constant Model Using Mueller Matrix Ellipsometry

2019 ◽  
Vol 9 (4) ◽  
pp. 698 ◽  
Author(s):  
Hao Jiang ◽  
Zhao Ma ◽  
Honggang Gu ◽  
Xiuguo Chen ◽  
Shiyuan Liu
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Minimum Mean Square Error ◽  
Incident Light ◽  
Mueller Matrix ◽  
Distribution Functions ◽  
Refractive Index Distribution ◽  
Index Distribution ◽  
Constant Distribution ◽  
Volume Gratings

Volume grating is a key optical component due to its comprehensive applications. Other than the common grating structures, volume grating is essentially a predesigned refractive index distribution recorded in materials, which raises the challenges of metrology. Although we have demonstrated the potential application of ellipsometry for volume grating characterization, it has been limited due to the absence of general forward model reflecting the refractive index distribution. Herein, we introduced a distributed dielectric constant based rigorous coupled-wave analysis (RCWA) model to interpret the interaction between the incident light and volume grating, with which the Mueller matrix can be calculated. Combining with a regression analysis with the objective to match the measured Mueller matrices with minimum mean square error (MSE), the parameters of the dielectric constant distribution function can be determined. The proposed method has been demonstrated using a series of simulations of measuring the volume gratings with different dielectric constant distribution functions. Further demonstration has been carried out by experimental measurements on volume holographic gratings recorded in the composite of polymer and zinc sulfide (ZnS) nanoparticles. By directly fitting the spatiotemporal concentration of the nanoparticles, the diffusion coefficient has been further evaluated, which is consistent to the result reported in our previous investigations.

Measurement of the dielectric function spectra of low dielectric constant using the spectroscopic ellipsometry

2003 ◽  
Author(s):  
Masahiro Horie ◽  
Kamil Postava ◽  
Tomuo Yamaguchi ◽  
Kumiko Akashika ◽  
Hideki Hayashi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Function ◽  
Spectroscopic Ellipsometry ◽  
Low Dielectric Constant ◽  
Low Dielectric

STUDY OF THE OPTICAL ABSORPTION OF Cu CLUSTERS IN THE Cu/ZnO SYSTEM

2001 ◽  
Vol 15 (17n19) ◽  
pp. 625-629 ◽  
Author(s):  
O. VAZQUEZ-CUCHILLO ◽  
A. BAUTISTA-HERNANDEZ ◽  
U. PAL ◽  
L. MEZA-MONTES
Keyword(s):  
Dielectric Constant ◽  
Optical Absorption ◽  
Free Path ◽  
Absorption Spectra ◽  
Effective Medium Theory ◽  
Composite Films ◽  
Mean Free Path ◽  
Optical Absorption Spectra ◽  
Medium Theory ◽  
Coated Nanoparticles

Optical absorption of Cu/ZnO composite films grown by r.f. sputtering are presented. We calculated the optical absorption spectra based on a colloidal-copper model with mean-free-path (MFP) and size corrections to the bulk dielectric constant. All effective-medium theory is used to analyze the presence of the coated nanoparticles and the ZnO matrix. The parameters of the model are fitted to reproduce the experimental spectra.

Dielectric Properties of Glass Capillary Arrays

1998 ◽  
Vol 511 ◽  
Author(s):  
T. E. Huber ◽  
Leo Silber ◽  
Frank Boccuzzi
Keyword(s):  
Dielectric Constant ◽  
Effective Medium Theory ◽  
Far Infrared ◽  
Soda Lime ◽  
Index Of Refraction ◽  
Soda Lime Glass ◽  
Frequency Range ◽  
Glass Capillary ◽  
Medium Theory ◽  
X Band

ABSTRACTGlass Capillary Arrays (GCA) are low density columnar monolithic structures made of soda-lime glass. This structure, in which 76% of volume between the columns, the channels, is void, also has a greatly reduced dielectric constant in comparison with bulk glass. We have measured the index of refraction and absorption of samples of GCA's in the X-band, 8 × 109 Hz to 1.2×1010 Hz, for various orientations of the channels with respect to the polarization. For channels perpendicular to the polarization direction we have measured an index of refraction of 1.15. In comparison the index of refraction of (bulk) soda-lime glass is 2.6. We also examined the absorption in the far-infrared (FIR) frequency range between 6×1011 Hz and 6×1012 Hz. In this frequency range we obtain a k2 dependence due to losses in the glass matrix at higher frequencies. The results of the X-band and FIR results are interpreted in terms of an effective medium theory of the real and imaginary part of the dielectric constant of the composite.

Sign in / Sign up

Export Citation Format

Share Document