An optical study of vacuum evaporated amorphous Ge20Te80−x Bi x thin films using transmission and reflection spectra

Sharma, Ambika; Barman, P. B.

doi:10.1007/s00340-009-3770-y

Cited by 22 publications

(8 citation statements)

References 28 publications

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“…The obtained data were very close to that data obtained before by Akrap et al for Se doped Bi 2 Te 3 crystals and seems to be in agreement with result in [78]. It has been reported in [79,80] that the electronegativity difference of the doping elements may be attributed to the lone pair p-orbital related to chalcogenide atoms (Te, Se) as well as to the variation in the values of the energy gap. Accordingly, the substitution of low electronegative elements in the site of high electronegative ones increases the energy of some lone pair states, broadening the valence band in the forbidden gap, leading to band tailing as well as shrinking the band gap.…”

Section: Electronic Thermal Conductivitysupporting

confidence: 91%

Preparation, structural characteristics and optical parameters of the synthesized nano-crystalline sulphur-doped Bi2Te2.85Se0.15 thermoelectric materials

Shalaby

Hashem

Yousif

et al. 2020

J Mater Sci: Mater Electron

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In the present work, a systematic preparation of Bi 2 Te 2.85 Se 0.15-x S x (x=0.0, 0.02, 0.04 and 0.06) compositions were carried out by solvothermal method. The materials were characterized by XRD, SEM, EDX, TEM and Raman spectroscopy.XRD, as well as TEM, to confirm the nanostructure of samples. The electrical and thermal properties were investigated in the temperature range from room temperature to 600 K. The highest power factor was 1.3 x 10 -2 mW/ K 2 m at 600 K for (x=0.06) sample. This improvement in the thermoelectric properties may be due to the ordered atomic arrangement of Bi, Te, and Se induced by sulphur in the Bi 2 Te 2.85 Se 0.15-x S x nano-composites, which was confirmed by X-ray diffraction (XRD) and Raman spectral analysis. The optical properties, such as energy gap, refractive index, extinction coefficient and dielectric constants, were obtained from the diffused reflectance data in the range of 200 to 800 nm. Sulphur doping influences the optical energy gap, reaching the lowest value for x=0.04 samples (0.14 eV), while the highest allowed energy gap was found in x=0.06 ones (0.41eV).

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Section: Electronic Thermal Conductivitysupporting

confidence: 91%

Preparation, structural characteristics and optical parameters of the synthesized nano-crystalline sulphur-doped Bi2Te2.85Se0.15 thermoelectric materials

Shalaby

Hashem

Yousif

et al. 2020

J Mater Sci: Mater Electron

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“…Figure 1 shows the transmission spectra of the thin films under investigation. 26 Swanepoel's envelope method 27,28 has been applied for the calculation of linear refractive index. 1 it is found that transmission decreases to ϳ70% when Bi ͑5 at.…”

Section: B Linear Refractive Indexmentioning

confidence: 99%

Linear and nonlinear refractive index of As–Se–Ge and Bi doped As–Se–Ge thin films

Sharma¹,

Katyal²

2010

Journal of Applied Physics

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Articles you may be interested inEffect of deposition parameters and semi-empirical relations between non-linear refractive index with linear refractive index and third order susceptibility for a-Ge20Se70-xIn10Bix thin films Measurement of the refractive index dispersion of As2Se3 bulk glass and thin films prior to and after laser irradiation and annealing using prism coupling in the near-and mid-infrared spectral range Rev. Sci. Instrum. 82, 053103 (2011); Refractive index change caused by electron irradiation in amorphous As-S and As-Se thin films coated with different metalsThe present work reports the linear and nonlinear refractive index for ͑As 2 Se 3 ͒ 90 Ge 10 and ͓͑As 2 Se 3 ͒ 90 Ge 10 ͔ 95 Bi 5 thin films. The formulation proposed by Fournier and Snitzer has been used to predict the nonlinear behavior of refractive index. The linear refractive index and Wemple-DiDomenico parameters were used for the determination of nonlinear refractive index in the wavelength region 0.4 to 1.5 m. Linear refractive index has been determined using the well known Swanepoel method. This is observed that nonlinear refractive index increases linearly with increasing linear refractive index. With Bi addition this has been found that nonlinear refractive index increases by 2.4 times, while on comparing with pure and doped silica glasses results are 2-3 orders higher. Density and molar volume has also been calculated. The obtained results may lead to yield more sensitive optical limiting devices and these glasses may be used as an optical material for high speed communication fibers.

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“…Nowadays, Ge 2 Sb 2 Te 5 (GST) material has been mainly used as the phase change material in PCM cells, due to the very remarkable difference in the optical reflectivity and electronic conductivity between amorphous and crystalline phases [3]. However, its high melting point and low crystalline resistance result in a high RESET current for the GST based device [4,5].…”

Section: Introductionmentioning

confidence: 99%

Advantages of Zn1.25Sb2Te3 material for phase change memory

Wang¹,

Nie²,

Shen³

et al. 2012

Materials Letters

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An optical study of vacuum evaporated amorphous Ge20Te80−x Bi x thin films using transmission and reflection spectra

Cited by 22 publications

References 28 publications

Preparation, structural characteristics and optical parameters of the synthesized nano-crystalline sulphur-doped Bi2Te2.85Se0.15 thermoelectric materials

Preparation, structural characteristics and optical parameters of the synthesized nano-crystalline sulphur-doped Bi2Te2.85Se0.15 thermoelectric materials

Linear and nonlinear refractive index of As–Se–Ge and Bi doped As–Se–Ge thin films

Advantages of Zn1.25Sb2Te3 material for phase change memory

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