A Simple Optical Properties Modeling of Microcrystalline Silicon by the Effective Medium Approximation Method

1996 ◽  
Vol 426 ◽  
Author(s):  
Woo Yeong Cho ◽  
Koeng Su Lim ◽  
Hyun-Mo Cho
Keyword(s):  
Optical Properties ◽  
Approximation Method ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Solar Spectrum ◽  
Effective Medium ◽  
Effective Medium Approximation ◽  
Microcrystalline Silicon ◽  
Two Phase ◽  
P Type

AbstractThe optical properties of microcrystalline silicon (µc-Si) were estimated using the EMA (Effective Medium Approximation) method. This modeling was based on two-phase mixture, amorphous silicon (a-Si) and crystalline silicon (c-Si) with volume fractions of fa and fc respectively. From this modeling, it could be possible to understand thatµc-Si has lower light absorption characteristics than a-Si over all solar spectrum by considering hydrogen involvement in embedded a-Si part of iic-Si and crystalline volume fraction. Also, it is proposed that p-type pe- Si is superior to n-type tic-Si because of its high optical gap of Eo4 and its low absorption coefficient spectrum shape.

A Simple Optical Properties Modeling of Microcrystalline Silicon by the Effective Medium Approximation Method

1996 ◽  
Vol 420 ◽  
Author(s):  
Woo Yeong Cho ◽  
Hyun-Mo Cho ◽  
Koeng Su Lim
Keyword(s):  
Optical Properties ◽  
Approximation Method ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Solar Spectrum ◽  
Effective Medium ◽  
Effective Medium Approximation ◽  
Microcrystalline Silicon ◽  
Two Phase ◽  
P Type

AbstractThe optical properties of microcrystalline silicon (μc-Si) were estimated using the EMA (Effective Medium Approximation) method. This modeling was based on two-phase mixture, amorphous silicon (a-Si) and crystalline silicon (c-Si) with volume fractions of fa and fc respectively. From this modeling, it could be possible to understand that μc-Si has lower light absorption characteristics than a-Si over all solar spectrum by considering hydrogen involvement in embedded a-Si part of μc-Si and crystalline volume fraction. Also, it is proposed that p-type μc-Si is superior to n-type μc-Si because of its high optical gap of Eo4 and its low absorption coefficient spectrum shape.

Employing the effective medium approximation to model the optical properties of crystallized a-Si:H obtained by MIC

2010 ◽  
pp. NA-NA
Author(s):  
T. F. G. Muller ◽  
D. Knoesen ◽  
C. J. Arendse ◽  
S. Halindintwali ◽  
G. F. Malgas ◽  
...  
Keyword(s):  
Optical Properties ◽  
Effective Medium ◽  
Effective Medium Approximation

Electrical and Optical Properties of Oxygenated Microcrystalline Silicon (mc-Si:O:H)

1992 ◽  
Vol 242 ◽  
Author(s):  
M. Faraji ◽  
Sunil Gokhale ◽  
S. M. Chaudhari ◽  
M. G. Takwale ◽  
S. V. Ghaisas
Keyword(s):  
Optical Properties ◽  
Glow Discharge ◽  
Silicon Surface ◽  
Volume Fraction ◽  
Crystalline Volume Fraction ◽  
Microcrystalline Silicon ◽  
Electrical And Optical Properties ◽  
Radio Frequency Glow Discharge ◽  
Absorption Studies ◽  
Discharge Method

ABSTRACTHydrogenated microcrystalline silicon with oxygen(mc-Si:O:H) is grown using radio frequency glow discharge method. Oxygen is introduced during growth by varying it's partial pressure in the growth chamber. The crystalline volume fraction ‘f’ and the crystallite size ‘δ’ are found to vary with the oxygen content. Results indicate that oxygen can etch the silicon surface when present in low amount while it forms a-SiO2-x with increasing contents. Optical absorption studies in the range of 2 to 3 eV suggest that the absorption coefficient ‘α’ lies in between the values of c-Si and a-Si:H.being closer to a-Si:H. The Hall mobility measurements for these samples indicate that for optimum oxygen contents the mobility as high as 35 cm2 V-1 sec-1 can be obtained. Results on I-V characteristics for p-i-n structure are presented.

On a Spring-Network Model and Effective Elastic Moduli of Granular Materials

1999 ◽  
Vol 66 (1) ◽  
pp. 172-180 ◽  
Author(s):  
K. Alzebdeh ◽  
M. Ostoja-Starzewaski
Keyword(s):  
Granular Materials ◽  
Disordered Systems ◽  
Granular Media ◽  
Elastic Moduli ◽  
Volume Fraction ◽  
Effective Medium ◽  
Solid State Physics ◽  
Two Phase ◽  
Effective Medium Theories ◽  
The Individual

Two challenges in mechanics of granular media are taken up in this paper: (i) development of adequate numerical discrete element models of topologically disordered granular assemblies, and (ii) calculation of macroscopic elastic moduli of such materials using effective medium theories. Consideration of the first one leads to an adaptation of a spring-network (Kirkwood) model of solid-state physics to disordered systems, which is developed in the context of planar Delaunay networks. The model employs two linear springs: a normal one along an edge connecting two neighboring vertices (grain centers) which accounts for normal interactions between the grains, as well as an angular one which accounts for angle changes between two edges incident onto the same vertex; edges remain straight and grain rotations do not appear. This model is then used to predict elastic moduli of two-phase granular materials—random mixtures of soft and stiff grains —for high coordination numbers. It is found here that an effective Poisson’s ratio, νeff, of such a mixture is a convex function of the volume fraction, so that νeff may become negative when the individual Poisson’s ratios of both phases are both positive. Additionally, the usefulness of three effective medium theories—perfect disks, symmetric ellipses, and asymmetric ellipses—is tested.

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.

Influence of the Grain Boundary Band Offset on Charge Transport Mechanism in Microcrystalline Silicon Analysed by Numerical Simulation

2000 ◽  
Vol 609 ◽  
Author(s):  
Alessandro Fantoni ◽  
Manuela Vieira ◽  
Reinhard Schwarz
Keyword(s):  
Charge Transport ◽  
Grain Boundaries ◽  
Transport Mechanism ◽  
Amorphous Matrix ◽  
Crystalline Silicon ◽  
Short Circuit ◽  
Band Offset ◽  
Charge Transport Mechanism ◽  
Microcrystalline Silicon ◽  
Two Phase

ABSTRACTMicrocrystalline silicon is a two-phase material composed of grains of crystalline silicon embedded in an amorphous silicon tissue. The boundary regions between the crystalline grains and the amorphous matrix are treated similarly to a heterojunction interface.The band offset at the grain boundaries causes the appearance of local electric field peaks, variables in intensity and direction. We present results obtained with two dimensional simulations of a μc-Si:H p-i-n junction in short circuit condition. Charge transport mechanism is described by the internal electric configuration assumed by the junction in thermodynamic equilibrium and illuminated with monochromatic radiations. Different configurations of the band offset at the grain boundaries are also considered and related to the transport properties in microcrystalline silicon

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