Free carrier absorption and the transient optical properties of amorphous silicon thin films: A model including time dependent free carrier, and static and dispersive interband contributions to the complex dielectric constant

Hydrogenated amorphous silicon (a-Si:H) thin films doped with both Phosphor and Nitrogen are deposited by ratio frequency plasma enhanced chemical vapor deposition (PECVD). The effect of gas flow rate of ammonia (FrNH3) on the composition, microstructure and optical properties of the films has been investigated by X-ray photoelectron spectroscopy, Raman spectroscopy and ellipsometric spectra, respectively. The results show that with the increase of FrNH3, Si-N bonds appear while the short-range order deteriorate in the films. Besides, the optical properties of N-doped n-type a-Si:H thin films can be easily controlled in a PECVD system.

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A New General Method for the Determination of Optical Properties of Amorphous Silicon Films

MRS Proceedings ◽

10.1557/proc-192-633 ◽

1990 ◽

Vol 192 ◽

Author(s):

G. Amato ◽

L. Boarino ◽

F. Fizzotti ◽

C. Manfredotti

Keyword(s):

Thin Films ◽

Optical Properties ◽

Amorphous Silicon ◽

Optical Response ◽

The Other ◽

New Method ◽

Silicon Thin Films ◽

Physical Insight ◽

General Method

ABSTRACTWe propose to apply a new method to model the optical response of amorphous silicon thin films. This method presents the advantage of having a good physical insight. On the other hand, although the model has been originally tested on different materials like a-Si, a-Ge and a-GaAs, we show that it is also sensitive to small differences like those that can exist between intrinsic and doped a-Si:H.

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Modification on Forouhi and Bloomer model for the optical properties of amorphous silicon thin films

Thin Solid Films ◽

10.1016/j.tsf.2006.11.003 ◽

2007 ◽

Vol 515 (7-8) ◽

pp. 3910-3913 ◽

Cited By ~ 13

Author(s):

Yong Liu ◽

Gang Xu ◽

Chenlu Song ◽

Wenjian Weng ◽

Piyi Du ◽

...

Keyword(s):

Thin Films ◽

Optical Properties ◽

Amorphous Silicon ◽

Silicon Thin Films

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Structural, Optical Constants and Photoluminescence of ZnO Thin Films Grown by Sol-Gel Spin Coating

Advances in Condensed Matter Physics ◽

10.1155/2013/234546 ◽

2013 ◽

Vol 2013 ◽

pp. 1-11 ◽

Cited By ~ 52

Author(s):

Abdel-Sattar Gadallah ◽

M. M. El-Nahass

Keyword(s):

Thin Films ◽

Dielectric Constant ◽

Refractive Index ◽

Spectral Range ◽

Spin Coating ◽

Optical Constants ◽

Sol Gel ◽

Free Carrier ◽

Zno Thin Films ◽

Free Carrier Absorption

We report manufacturing and characterization of low cost ZnO thin films grown on glass substrates by sol-gel spin coating method. For structural properties, X-ray diffraction measurements have been utilized for evaluating the dominant orientation of the thin films. For optical properties, reflectance and transmittance spectrophotometric measurements have been done in the spectral range from 350 nm to 2000 nm. The transmittance of the prepared thin films is 92.4% and 88.4%. Determination of the optical constants such as refractive index, absorption coefficient, and dielectric constant in this wavelength range has been evaluated. Further, normal dispersion of the refractive index has been analyzed in terms of single oscillator model of free carrier absorption to estimate the dispersion and oscillation energy. The lattice dielectric constant and the ratio of free carrier concentration to free carrier effective mass have been determined. Moreover, photoluminescence measurements of the thin films in the spectral range from 350 nm to 900 nm have been presented. Electrical measurements for resistivity evaluation of the films have been done. An analysis in terms of order-disorder of the material has been presented to provide more consistency in the results.

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Influence of Film Thickness on Optical Properties of Hydrogenated Amorphous Silicon Thin Films

Egyptian Journal of Solids ◽

10.21608/ejs.2008.148818 ◽

2008 ◽

Vol 31 (1) ◽

pp. 11-22 ◽

Cited By ~ 1

Keyword(s):

Thin Films ◽

Optical Properties ◽

Film Thickness ◽

Amorphous Silicon ◽

Hydrogenated Amorphous Silicon ◽

Silicon Thin Films ◽

Hydrogenated Amorphous

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Free Carrier Absorption in P-Type Epitaxial Si and GaAs Films for far-Infrared Detection

MRS Proceedings ◽

10.1557/proc-484-199 ◽

1997 ◽

Vol 484 ◽

Author(s):

A. O. U. Perera ◽

W. Z. Shen ◽

M. O. Tanner ◽

K. L. Wang ◽

W. Schaff

Keyword(s):

Thin Films ◽

Absorption Coefficient ◽

Far Infrared ◽

Infrared Region ◽

Free Carrier ◽

Photon Absorption ◽

Free Carrier Absorption ◽

Absorption Data ◽

Carrier Absorption ◽

P Type

AbstractWe report the investigation of free-carrier absorption characteristics for epitaxially grown p-type thin films in the far-infrared region (50 ∼ 200 μm), where homojunction interfacial workfunction internal photoemission (HIWIP) detectors are employed. Five Si and three GaAs thin films were grown by MBE over a range of carrier concentrations, and the experimental absorption data were compared with calculated results. The freehole absorption is found to be almost independent of the wavelength. A linear regression relationship between the absorption coefficient and the carrier concentration, in agreement with theory, has been obtained and employed to calculate the photon absorption probability in HIWIP detectors. The detector responsivity follows the quantum efficiency predicted by concentration dependence of the free carrier absorption coefficient.

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In Situ Fast Temperature Measurement of Silicon Thin Films during the Excimer Laser Annealing

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.195 ◽

2006 ◽

Vol 326-328 ◽

pp. 195-198

Author(s):

Seung Jae Moon

Keyword(s):

Thin Films ◽

Optical Properties ◽

Melting Point ◽

Temperature Measurement ◽

Amorphous Silicon ◽

Laser Annealing ◽

Crystalline Silicon ◽

Excimer Laser Annealing ◽

Silicon Thin Films

The formation and growth mechanism of polysilicon grains in thin films via laser annealing of amorphous silicon thin films are studied. The complete understanding of the mechanism is crucial to improve the thin film transistors used as switches in the active matrix liquid crystal displays. To understand the recrystallization mechanism, the temperature history and liquidsolid interface motion during the excimer laser annealing of 50-nm thick amorphous and polysilicon films on fused quartz substrates are intensively investigated via in-situ time-resolved thermal emission measurements, optical reflectance and transmittance measurements at near infrared wavelengths. The front transmissivity and reflectivity are measured to obtain the emissivity at the 1.52 μm wavelength of the probe IRHeNe laser to improve the accuracy of the temperature measurement. The melting point of amorphous silicon is higher than that of crystalline silicon of 1685 K by 100-150 K. This is the first direct measurement of the melting temperature of amorphous silicon thin films. It is found that melting of polysilicon occurs close to the melting point of crystalline silicon. Also the optical properties such as reflectance and transmittance are used to determine the melt duration by the detecting the difference of the optical properties of liquid silicon and solid silicon.

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