Optical properties of Microcrystalline Silicon determined by Spectroscopic Ellipsometry and Photothermal Deflection Spectroscopy

2002 ◽  
Vol 715 ◽  
Author(s):  
Kyung Hoon Jun ◽  
Helmut Stiebig ◽  
Reinhard Carius
Keyword(s):  
Optical Properties ◽  
Spectroscopic Ellipsometry ◽  
Volume Fraction ◽  
Large Deviation ◽  
Effective Medium Theory ◽  
Dense Medium ◽  
Medium Theory ◽  
Enhanced Absorption ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection

AbstractThe effect of the microstructure and bonded hydrogen on the optical properties of microcrystalline films (μc-Si:H) was investigated by Spectroscopic Ellipsometry (SE) and Photothermal Deflection Spectroscopy (PDS). On samples with a high crystalline volume fraction we studied the reason for a large deviation of absorption coefficient in the energy range between 1.6 eV and 3.2 eV from the value predicted by effective medium theory. This enhancement can be attributed to scattering by the inhomogeneity of μc-Si:H, which is investigated by the introduction of the dense medium radiative transfer formalism to an optical scattering simulation. Further, we suggest strain as a reason for the enhanced absorption in highly crystalline μc-Si:H.

scholarly journals Photothermal Deflection Spectroscopy Study of Nanocrystalline Si (nc-Si) Thin Films Deposited on Porous Aluminum with PECVD

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
S. Ktifa ◽  
M. Ghrib ◽  
F. Saadallah ◽  
H. Ezzaouia ◽  
N. Yacoubi
Keyword(s):  
Optical Properties ◽  
Energy Gap ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Porous Aluminum ◽  
Force Microscopy ◽  
Photothermal Deflection Spectroscopy ◽  
Atomic Force ◽  
Photothermal Deflection ◽  
Morphology Characterization

We have studied the optical properties of nanocrystalline silicon (nc-Si) film deposited by plasma enhancement chemical vapor deposition (PECVD) on porous aluminum structure using, respectively, the Photothermal Deflection Spectroscopy (PDS) and Photoluminescence (PL). The aim of this work is to investigate the influence of anodisation current on the optical properties of the porous aluminum silicon layers (PASL). The morphology characterization studied by atomic force microscopy (AFM) technique has shown that the grain size of (nc-Si) increases with the anodisation current. However, a band gap shift of the energy gap was observed.

scholarly journals A proof that multiple waves propagate in ensemble-averaged particulate materials

2019 ◽  
Vol 475 (2229) ◽  
pp. 20190344 ◽  
Author(s):  
Artur L. Gower ◽  
I. David Abrahams ◽  
William J. Parnell
Keyword(s):  
Acoustic Waves ◽  
Volume Fraction ◽  
Effective Medium Theory ◽  
Effective Medium ◽  
Inhomogeneous Material ◽  
Ensemble Averaging ◽  
Reflection And Transmission ◽  
Medium Theory ◽  
Transmission Coefficients ◽  
Cylindrical Inclusions

Effective medium theory aims to describe a complex inhomogeneous material in terms of a few important macroscopic parameters. To characterize wave propagation through an inhomogeneous material, the most crucial parameter is the effective wavenumber . For this reason, there are many published studies on how to calculate a single effective wavenumber. Here, we present a proof that there does not exist a unique effective wavenumber; instead, there are an infinite number of such (complex) wavenumbers. We show that in most parameter regimes only a small number of these effective wavenumbers make a significant contribution to the wave field. However, to accurately calculate the reflection and transmission coefficients, a large number of the (highly attenuating) effective waves is required. For clarity, we present results for scalar (acoustic) waves for a two-dimensional material filled (over a half-space) with randomly distributed circular cylindrical inclusions. We calculate the effective medium by ensemble averaging over all possible inhomogeneities. The proof is based on the application of the Wiener–Hopf technique and makes no assumption on the wavelength, particle boundary conditions/size or volume fraction. This technique provides a simple formula for the reflection coefficient, which can be explicitly evaluated for monopole scatterers. We compare results with an alternative numerical matching method.

Electronic and Optical Properties of a-Si1−xCx:H Films Produced From Admixtures of Silane and Ditertiarybutylsilane

1994 ◽  
Vol 336 ◽  
Author(s):  
K. Gaughan ◽  
J.M. Viner ◽  
P.C. Taylor
Keyword(s):  
Electrical Conductivity ◽  
Silicon Carbide ◽  
Optical Properties ◽  
Chemical Vapor Deposition ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Photothermal Deflection Spectroscopy ◽  
Optical And Electronic Properties ◽  
Photothermal Deflection

ABSTRACTWe investigated the optical and electronic properties of amorphous silicon carbide (a-Si1−xCx:H) films produced by plasma enhanced chemical vapor deposition from admixtures of silane and ditertiarybutylsilane [SiH2 (C4H9) 2 or DTBS] using photothermal deflection spectroscopy, electrical conductivity and its temperature dependence as well as photoconductivity. These a-Si1−xCx:H films exhibit low Urbach energies and high photoconductivities similar to films produced with other carbon feedstock sources. We also present our results for hydrogen diluted a-Si1−xCx:H films using DTBS as the carbon feedstock source.

Electronic Properties of Microcrystalline Silicon

1997 ◽  
Vol 467 ◽  
Author(s):  
R. Carius ◽  
F. Finger ◽  
U. Backhausen ◽  
M. Luysberg ◽  
P. Hapke ◽  
...  
Keyword(s):  
Vapour Deposition ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Chemical Vapour ◽  
Structural Defects ◽  
Photoluminescence Properties ◽  
Crystalline Volume Fraction ◽  
Microcrystalline Silicon ◽  
Photothermal Deflection Spectroscopy ◽  
Photothermal Deflection

ABSTRACTThe electronic and optical properties of microcrys tall ine silicon films prepared by plasma enhanced chemical vapour deposition are investigated with Hall-effect, electrical conductivity, photothermal deflection spectroscopy and photoluminescence measurements. In particular, the influence of the grain size and the crystalline volume fraction on the conductivity, the carrier density and the Hall mobility is investigated in highly doped films. A percolation model is proposed to describe the observed transport data. Photoluminescence properties were studied in un-doped films. It is proposed that the photoluminescence is due to recombination at structural defects similar to those observed in crystalline silicon.

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