Optical properties of amorphous chalcogenide thin films: The effect of Te isovalence substitution in the Ge-S-Se system

Sedeek, K.; Mahmoud, E. A.; Terra, F. S.; Said, Ali; El-Din, S M

doi:10.1088/0022-3727/27/1/024

Cited by 30 publications

(4 citation statements)

References 16 publications

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“…The absorption coefficient (a) has been estimated for all samples from the following expression [9]:…”

Section: Optical Absorption Spectroscopymentioning

confidence: 99%

Study on Different Solution-Cast Films of PMMA and PVAc

Ahmed

2008

International Journal of Polymeric Materials and Polymeric Biom

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Transparent films of PMMA (poly methyl methacrylate) and PVAc (polyvinyl acetate), previously dissolved in chloroform, toluene and tetrahydrofuran (THF), were prepared by using solution-cast technique. FT-IR transmission spectra were obtained from the samples. Also, different concentrations of PMMA=PVAc blend, dissolved in chloroform, were prepared by the same method. From absorption, transmission and specular reflection spectra, the absorption coefficient (a) and refractive index (n) have been calculated at room temperature and also after heating. The values of the optical band gap (E g ) have been obtained from the direct allowed transitions in k-space. In addition, the values of width of the tails of localized states in the band gap (E u ) were evaluated from Urbach edges.

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“…The absorption coefficient (a) has been estimated for all samples from the following expression [9]:…”

Section: Optical Absorption Spectroscopymentioning

confidence: 99%

Study on Different Solution-Cast Films of PMMA and PVAc

Ahmed

2008

International Journal of Polymeric Materials and Polymeric Biom

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“…The effect of changing the germanium content in Ge x Se 1-x films on its optical properties, has been discussed. The optical band gap (E g ), the width of the localized tail states (Urbach's tail) (E u ) and the width of the refractive index (n) can be calculated by measuring the optical absorption coefficient (α), using the equation [28,29]: where T o and T are the intensity of the incident and transmitted light respectively, A-is the absorbance and d-is the film thickness. The optical absorption measurements of Ge x Se 1-x films, for different compositions have been performed and analyzed to give a qualitative descriptions of the structural dependence near the band edge.…”

Section: Further Investigation Have Been Done By Measuring the Ir Tramentioning

confidence: 99%

“…The optical band gap (E g ) can be calculated from the extrapolation of the linear portions of the lines Fig. 5 to (αhν) 1/2 = 0 according to the relation [28][29][30]:…”

Section: Further Investigation Have Been Done By Measuring the Ir Tramentioning

confidence: 99%

Structural Properties of GexSe1-x Thin Films Prepared by Semi-closed Space Technique

2000

Egyptian Journal of Solids

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Bulk and thin film Ge x Se 1-x alloys have been prepared with 0.1≤X≤0.5. The bulk materials were obtained by quenching from the melt. They have been used as source materials to produce thin film samples using the thermal evaporation method (semi-closed space technique). The composition of the obtained films was checked against the bulk ones by X-ray fluorescence (XRF) technique. X-ray diffraction patterns of the obtained compositions revealed the presence of some crystalline inclusions in the amorphous matrix for some compositions. Glass transition temperature measurements showed a maximum in the range X=0.25 to 0.32 where the glass forming ability is optimum. Measurements of the temperature dependence of the steady state dark current as a function of the Ge content has been recorded during heating and cooling cycles. A compensation effect has been found and characterized with two compensation temperatures, during the cooling cycle. Optical transmission, (UV) and infrared (IR), measurements have been performed. Energy band gap, width of the band tail and the refractive index have been calculated. Results have been interpreted in terms of the structural behavior of the samples under investigation in view of the models presented in literatures.

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“…Materials are provided as thin films in device fabrication. The parameters controlling the properties of thin films are structure (Hagenmuller, 1990), composition (Sedeek et al, 1994 andSenthile et al, 2002), film thickness (El-Nahass et al, 2002 andSoliman et al, 1998), faults probability (Rouxel, et al, 1994) and the presence of impurities (Wiegers, 1989).…”

Section: Introductionmentioning

confidence: 99%

Electrical Conduction Mechanisms and Dielectric Constants of Nanostructure Zinc Indium Selenide Thin Films

Zeyada¹,

Youssif²,

El-Ghamaz³

et al. 2015

Scientific Journal for Damietta Faculty of Science

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ZnIn 2 Se 4 has polycrystalline structure in as synthesized powder form; it becomes nanocrystallites upon thermal deposition. The crystallite size increases by increasing annealing temperature. The radial distribution function showed that in the first short range order shell; Se atom is tetrahedral surrounded by a vacancy and three cationic sites occupied by the metal atoms in the ratio 2/3 of In and 1/3 of Zn. The medium range order region is attributed to In-In pairs having a layered structure of connected distorted octahedral. The direct current density-voltage characteristics for Au / ZnIn 2 Se 4 / Au of planar structure revealed three conduction mechanisms depending on applied potential; namely they are consequently generation-recombination, Ohmic and exponential trap space charge limited conduction mechanisms. The AC electrical conductivity and dielectric relaxation of ZnIn 2 Se 4 thin films in the temperature range 305-493 K and in frequency range 1 kHz -4M Hz has also been studied. Analysis of ln ac -ln ω curves showed that band-type conduction process occurs in frequency range < 1945 Hz. For frequencies > 1945 Hz,  ac increases linearly with the increase in frequency and this is associated with hopping type conduction mechanism. Analysis of these results proved that conduction occurs by phonon assisted hopping between localized states and it is performed by bipolaron hopping mechanism. The temperature and frequency dependence of both the real and imaginary parts of the dielectric constant have been investigated..

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Optical properties of amorphous chalcogenide thin films: The effect of Te isovalence substitution in the Ge-S-Se system

Cited by 30 publications

References 16 publications

Study on Different Solution-Cast Films of PMMA and PVAc

Study on Different Solution-Cast Films of PMMA and PVAc

Structural Properties of GexSe1-x Thin Films Prepared by Semi-closed Space Technique

Electrical Conduction Mechanisms and Dielectric Constants of Nanostructure Zinc Indium Selenide Thin Films

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