Electrical and optical properties of bismuth sulphotelluride [Bi2(S1−xTex)3] thin films prepared by arrested precipitation technique (APT)

Mane, R.K.; Ajalkar, Balu D.; Bhosale, Popatrao N.

doi:10.1016/s0254-0584(03)00333-x

Cited by 16 publications

(11 citation statements)

References 15 publications

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“…[14][15][16][17][18] More recently, thin films were characterized by classical optical methods. [19][20][21][22] Only one work 20 was reported on thin films obtained by metallorganic chemical vapor deposition using spectroscopic ellipsometry ͑SE͒ in the visible range. Ellipsometry is an optical method for surface analysis based on the measurement of the change of the polarization state of a light beam during reflection.…”

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confidence: 99%

Infrared and Visible Dielectric Function of Electroplated Bi[sub 2±x]Te[sub 3±x] Films Determined by Spectroscopic Ellipsometry

Zimmer

Stein

Johann

et al. 2005

J. Electrochem. Soc.

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The pseudodielectric functions of electroplated Bi 2±x Te 3±x thin films with atomic bismuth content varying from 1.8 to 2.2 were determined using spectroscopic ellipsometry in the energy range of 0.03-3.10 eV. The experimental dielectric functions show differences with the literature bulk single-crystal data which may be explained by a ca. 50% porosity in the electroplated films. In the visible range, the optical constants did not seem to depend on the film composition while in the infrared range a rough tendency can be established: the real part of the dielectric function shifted to lower values with increasing bismuth content while the imaginary part shifted toward higher values. In the infrared range, Tauc-Lorentz combined with Drude dispersion relations were successfully used. The energy bandgap E g was found to be about 0.11 eV independent of the film composition. This result is related to the minor evolution of the film composition. Moreover, the fundamental absorption edge was described by an indirect optical band-to-band transition. The thickness of the thinner films were estimated, which are comprised between 1.77 and 1.99 m following the samples. Electrical resistivity and energy-independent scattering time were found to be related to the bismuth content.V-VI binary compounds such as Bi 2 Te 3 , Sb 2 Te 3 , and Bi 2 Se 3 are narrow bandgap semiconductors. They are becoming quite interesting as materials for thermoelectric devices. Due to their high figureof-merit at room temperature, bismuth telluride ͑Bi 2 Te 3 ͒ and its selenide and antimony-doped compounds are considered to be the best materials for thermoelectric applications. 1 Many deposition techniques, such as sputtering, 2-4 metallorganic chemical vapor deposition, 5,6 and molecular beam epitaxy, 7-9 have been used to obtain thin films of bismuth telluride compounds. These deposition techniques have as drawback a rather high production cost. Electrodeposition 10-12 may offer a low-cost film growth method with a high deposition rate. Several electrochemical processes have been developed, leading to different compositions of Bi 2 Te 3 binary compounds. 12,13 The stoichiometry of these thermoelectric films directly influences their electronic and transport properties.Due to both experimental interest and theoretical importance, the optical properties of Bi 2 Te 3 were studied using crystals or thin films. The first results were performed on ingots with transmittance and reflectance measurements methods. 14-18 More recently, thin films were characterized by classical optical methods. [19][20][21][22] Only one work 20 was reported on thin films obtained by metallorganic chemical vapor deposition using spectroscopic ellipsometry ͑SE͒ in the visible range. Ellipsometry is an optical method for surface analysis based on the measurement of the change of the polarization state of a light beam during reflection. 23 From ellipsometry, the dielectric function of bulk materials is obtained analytically, while for thin films appropriate fitting is needed. Th...

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mentioning

confidence: 99%

Infrared and Visible Dielectric Function of Electroplated Bi[sub 2±x]Te[sub 3±x] Films Determined by Spectroscopic Ellipsometry

Zimmer

Stein

Johann

et al. 2005

J. Electrochem. Soc.

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“…By knowing thickness of sample and measured absorbance, it was observed that value of the absorption coefficient (a) lies in the range of 10 4 cm -1 . High absorption coefficient suggested direct and allowed optical transition [13,22]. The fundamental absorption edge in most of metal chalcogenide follows an exponential law.…”

Section: Characterizationsmentioning

confidence: 98%

“…The binary bismuth and molybdenum based selenide thin film nanostructures have been applied in various sectors of energy such as photovoltaic solar cells, lithium ion battery, hydrogen evolution, thermoelectric devices [3][4][5][6][7][8], etc. Various deposition methods, can be used for deposition of binary, ternary and quaternary metal chalcogenide thin films such as chemical vapor deposition, spray pyrolysis, chemical bath deposition, electroless deposition, microwave assisted synthesis, arrested precipitation technique, and vacuum evaporation [2,5,[8][9][10][11][12][13][14] etc. The work on bismuth and molybdenum based chalcogenide thin films for solar cell application has been started recently.…”

Section: Introductionmentioning

confidence: 99%

“…However, very little efforts have been devoted for the device fabrication of this type material. It has been reported that MoBi 2 Se 5 thin films have n-type conductivity and is photoactive in the visible region of the solar spectrum [13,15]. The deposition of metal selenide thin films is encountered with various problems of obtaining a polyphasic mixture.…”

Section: Introductionmentioning

confidence: 99%

“…The detailed process is discussed elsewhere [13]. Finally dried powder of MoBi 2 Se 5 is used as a single source for vacuum evaporation.…”

Section: Introductionmentioning

confidence: 99%

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Single source precursor for vacuum evaporation of MoBi2Se5 photoactive thin films

Mohite

Mali

Kharade

et al. 2015

J Mater Sci: Mater Electron

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In this paper, we report a new approach for deposition of nanocrystalline MoBi 2 Se 5 thin films using vacuum evaporation employing single source precursor synthesized by arrested precipitation technique. As deposited and vacuum annealed MoBi 2 Se 5 thin films were characterized for opto-structural, morphological, compositional and electrochemical analysis. It was observed that optical band gap decreases from 2.07 eV to 1.87 eV with vacuum annealing. X-ray diffraction studies confirm rhombohedral crystal structure of MoBi 2 Se 5 thin films. Scanning electron microscopy images show compact arrangement of spherical grains without pin holes. Transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) results reveal nanocrystalline nature having particle size *100 nm and selected area electron diffraction (SAED) pattern confirms rhombohedral crystal structure. The compositional analysis done by XPS shows presence of Mo 4? , Bi 3? and Se 2-oxidation states confirming stoichiometric MoBi 2 Se 5 thin film material. The photoelectrochemical (PEC) parameters of as deposited and vacuum annealed thin films were recorded in 0.5 M aqueous polysulfide electrolyte. Our PEC results show that 0.57 and 0.70 % conversion efficiency for as-deposited and vacuum annealed samples respectively.

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Effect of copper content on optostructural, morphological and photoelectrochemical properties of MoBi2−x Cu x Se4 thin films

et al. 2013

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Electrical and optical properties of bismuth sulphotelluride [Bi2(S1−xTex)3] thin films prepared by arrested precipitation technique (APT)

Cited by 16 publications

References 15 publications

Infrared and Visible Dielectric Function of Electroplated Bi[sub 2±x]Te[sub 3±x] Films Determined by Spectroscopic Ellipsometry

Infrared and Visible Dielectric Function of Electroplated Bi[sub 2±x]Te[sub 3±x] Films Determined by Spectroscopic Ellipsometry

Single source precursor for vacuum evaporation of MoBi2Se5 photoactive thin films

Effect of copper content on optostructural, morphological and photoelectrochemical properties of MoBi2−x Cu x Se4 thin films

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