Thickness dependence of electrical resistivity and activation energy in AgSbTe2 thin films
01 Jun 1993-Journal of Materials Science: Materials in Electronics (Kluwer Academic Publishers)-Vol. 4, Iss: 2, pp 183-186
TL;DR: In this article, thin films of AgSbTe2 with different thicknesses were prepared by thermal evaporation on glass substrates held at room temperature and the films were all found to be semiconducting in nature.
Abstract: Thin films of AgSbTe2 with different thicknesses were prepared by thermal evaporation on glass substrates held at room temperature. The films were all found to be semiconducting in nature. The film resistivity was found to be a function of inverse thickness and was discussed on the basis of the effective mean free path model. The activation energy was found to be a linear function of the inverse square of film thickness. It was attributed to the quantization of the momentum component of charge carriers normal to the film plane.
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TL;DR: In this article, the mean free path of charge carriers in CoPc thin films and bulk resistivity was estimated using the CBH model with centers of intimate valence alternation pairs type with a maximum barrier height of 1.594 eV.
Abstract: Thin films of CoPc of various thickness have been deposited onto glass substrates using thermal evaporation technique at room temperature. The dark electrical resistivity measurements were carried out at different temperature range (298–423 K). An estimation of mean free path () of charge carriers in CoPc thin films and bulk resistivity, was attempted. Measurements of thermoelectric power confirm that CoPc thin films behave as p -type semiconductors. The ac conductivity ( σ ac ) has been investigated in the frequency range (10 2 –10 6 Hz) and temperature range (298–407 K). σ ac is found to be proportional to ω s where s ≈ 0.879 which is frequency and temperature independence. The ac conductivity interpreted by the correlated barrier hopping (CBH) model with centers of intimate valence alternation pairs type with a maximum barrier height, W M ≈ 1.594 eV.
38 citations
TL;DR: In this paper, the dark electrical resistivity calculations were carried out at different elevated temperatures in the range 303-423 K and in thickness range 235-457 nm and the results obtained are discussed in terms of the non-overlapping small polaron tunneling model.
Abstract: Cadmium thiogallate CdGa2S4 thin films were prepared using a conventional thermal evaporation technique. The dark electrical resistivity calculations were carried out at different elevated temperatures in the range 303–423 K and in thickness range 235–457 nm. The ac conductivity and dielectric properties of CdGa2S4 film with thickness 457 nm has been studied as a function of temperature in the range from 303 to 383 K and in frequency range from 174 Hz to 1.4 MHz. The experimental results indicate that σac(ω) is proportional to ωs and s ranges from 0.674 to 0.804. It was found that s increases by increasing temperature. The results obtained are discussed in terms of the non overlapping small polaron tunneling model. The dielectric constant (e′) and dielectric loss (e″) were found to be decreased by increasing frequency and increased by increasing temperature. The maximum barrier height (Wm) was estimated from the analysis of the dielectric loss (e″) according to Giuntini’s equation. Its value for the as-deposited films was found to be 0.294 eV.
21 citations
TL;DR: In this article, thin films of H2Pc of various thicknesses have been deposited onto glass substrates using thermal evaporation technique at room temperature, and the dark electrical resistivity calculations were carried out at different temperatures in the range 298-473 K.
19 citations
TL;DR: In this paper, the effect of NiTPP film thickness (160-460 nm) and isochronal annealing in temperature range (300-348 K) on DC electrical properties were studied.
Abstract: 5,10,15,20-Tetraphenyl-21H, 23H-porphyrin nickel(II), NiTPP films were prepared by thermal evaporation method of mother powder material. Electrical as well as thermo-electric properties were investigated for the as-deposited and annealed NiTPP films. The effect of NiTPP film thickness (160–460 nm) and isochronal annealing in temperature range (300–348 K) on DC electrical properties were studied. Both bulk resistivity and the mean free path were determined; their values are 1.38 × 105 Ω cm and 0.433 nm, respectively. The electrical conductivity exhibits intrinsic and extrinsic conduction. The values of activation energy in extrinsic and intrinsic regions are 0.204 and 1.12 eV, respectively. Mott’s parameters were determined at low temperature. Seebeck coefficient indicates p-type conduction of NiTPP films. Carrier density, mobility and holes concentration were determined. Seebeck coefficient decreases with the increasing of temperature, while the conductivity increases with the increasing of temperature. The difference between the conductivity and the thermoelectric power activation energies was attributed to the potential barrier grain boundaries.
16 citations
TL;DR: In this paper, two kinds of chalcogenide films with similar Sb/Te atomic ratios, AgInSbTe (AIST) and SbTe(ST) were deposited on alkali-free glass using the RF sputtering method.
Abstract: Two kinds of chalcogenide films with similar Sb/Te atomic ratios, AgInSbTe (AIST) and SbTe (ST) were deposited on alkali-free glass using the RF sputtering method. The microstructure characteristics of both ST and AIST films were demonstrated to correlate with the electrical properties. TEM observation and GI-XRD profiles revealed that the structures of as-deposited AIST and ST films were amorphous characteristics. The sheet resistance of the as-deposited AIST films was twice as high as that of ST films and the effect of Ag and In additives was proposed. After annealing at 523 K for 1 h, the sheet resistance of both chalcogenide films decreased by four orders of magnitude due to crystallizations and the sheet resistance of crystallized AIST film was still twice as large as that of crystallized ST film. DSC measurement was used to determine the crystallization temperature of AIST films as 476 K and that of ST films as 445 K. The activation energies of crystallization were determined using Kissinger’s method, and 0.94 eV and 0.84 eV were obtained for AIST and ST films, respectively. TEM observations showed that AgSbTe2 phase exists in the AIST film after heat treatment in addition to � -Sb phase. No indium compounds were discovered in the AIST film by the energy dispersive spectroscopy (EDS) and XRD measurements. [doi:10.2320/matertrans.48.610]
11 citations
References
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01 Jan 1969
2,189 citations
"Thickness dependence of electrical ..." refers background in this paper
...The well-known classical size effect theory, which takes into account surface scattering in addition to bulk scattering, gives the resistivity p of a thin film of thickness t as [ 7 ]...
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...The free electron model (spherical Fermi surface) gives the carrier concentration as [ 7 ] 1 _ [ 1 -]l/3e2n2/3 Ooto fi (3)...
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TL;DR: In this paper, the Widmanstatten precipitate of Sb2Te3 upon the {111} planes of the matrix face centered cubic material was identified as a fine twin lamellas.
Abstract: X‐ray, optical and electron microscope, and chemical etching techniques have been used to investigate a striated microstructure observed in zone refined single crystals of the AgSbTe2 structure. This microstructure, originally thought to be fine twin lamellas, has been identified as a Widmanstatten precipitate of Sb2Te3 upon the {111} planes of the matrix face‐centered cubic material. In addition, the evidence obtained from all the measurements made on this material indicates that the ternary compound of the AgSbTe2 type does not melt congruently.
67 citations
TL;DR: By starting from the Mayadas-Shatzkes model an effective mean free path l g is defined to describe electronic conduction in thin polycrystalline metallic films; the Fuchs-Sondheimer model can then be used to calculate the film resistivity and its temperature coefficient.
63 citations
58 citations
TL;DR: In this paper, the electrical resistance of Ag2Te films has been measured as a function of temperature during heating, which was carried out immediately after the film formation, and the observed exponential decrease of resistance with temperature up to the transition point points to the semiconducting nature of the low temperature polymorph of ag2Te.
Abstract: Thin films of Ag2Te of various thicknesses in the range 500–1500 A have been prepared by thermal evaporation of the compound under vacuum on clean glass substrates held at room temperature. The electrical resistance of the films has been measured as a function of temperature during heating, which was carried out immediately after the film formation. The observed exponential decrease of resistance with temperature up to the transition point points to the semiconducting nature of the low temperature polymorph of Ag2Te. The band gap of the low temperature phase is calculated for various thicknesses of the films and it is found that the band gap is a function of film thickness, increasing with decreasing thickness. The increase in the band gap, which was found to be inversely proportional to the square of the film thickness, is attributed to quantization of electron momentum component normal to film plane.
25 citations