Electronic conduction in Bi‐modified amorphous thin films of Ge20Te80‐x Bi x exhibiting an absence of a p‐n transition

Bhatia, K.L.; Singh, Mahender; Kishore, N.; Suzuki, Masakuni

doi:10.1080/01418639609365832

Cited by 12 publications

(6 citation statements)

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“…The results show that the two processes of electric conduction by bipolaron hopping between non-randomly distributed defect sites and single-polaron hopping between randomly distributed defect sites are present in all the four compositions, with the former process predominating at lower temperatures and the latter at higher temperatures. The situation here is similar to that for many other chalcogenide glasses which contain bismuth or lead and exhibit p-n transitions [6,[15][16][17][18][19].…”

Section: The Ac Conductivitysupporting

confidence: 73%

Alternating-current conductivity and dielectric properties of Ge₂₅Sb_15-xBi_xS₆₀bulk and thin-film glasses

El-Samanoudy

2002

J. Phys.: Condens. Matter

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The effect of the replacement of antimony atoms by bismuth atoms on the electrical properties of compounds of the melt-quenched and thermally evaporated Ge25Sb15-xBixS60 (x = 0, 5, 10 and 15) chalcogenide system are reported for the first time. The results for the alternating-current (ac) conductivity σac and the dielectric constant ϵ1 of some bulk and thin-film samples of the four different compositions are presented over the temperature range 134-373 K and the frequency range 0.1-100 kHz. The ac conductivity increases with increase in the Bi content and deposition rate and decreases with increase in the film thickness. Its frequency exponent s exhibits strong temperature dependence. Analysis of the results in the light of the correlated barrier-hopping model for ac conduction reveals that electronic conduction takes place by single-polaron and bipolaron hopping processes at high and low temperatures respectively. The effects of composition, temperature, deposition rate and film thickness on the dielectric constant and the loss factor are studied. The dielectric constant and the loss factor are found to increase with increase of the Bi content and the deposition rate, especially at high temperatures and low frequencies. It is also found that increase in the film thickness leads to increase of the dielectric constant. The values of the electrical conductivity of the thin-film samples are higher by over one order of magnitude than those of the corresponding bulk samples, a fact that can be attributed to the higher density of defect states in the former.

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Section: The Ac Conductivitysupporting

confidence: 73%

Alternating-current conductivity and dielectric properties of Ge₂₅Sb_15-xBi_xS₆₀bulk and thin-film glasses

El-Samanoudy

2002

J. Phys.: Condens. Matter

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“…This unique property of the amorphous thin film of Ge-Te-Bi makes this an interesting system of semiconductors. We have reported the results of our recent experiments on this class of material in thin-film form [6,7]. In this paper, we undertake an investigation of the optical and electrical properties of thermally annealed thin films Ge 20 Te 80−x Bi x for the first time and we report on the results of this study.…”

Section: Introductionmentioning

confidence: 97%

“…The two systems, Ge-S-Bi and Ge-Se-Bi, exhibit carrier sign reversal (p-n transition) in both bulk and thin-film forms. However, the Ge-Te-Bi system shows p-n transition in bulk form and no carrier sign reversal is found in thin-film form [6]. This unique property of the amorphous thin film of Ge-Te-Bi makes this an interesting system of semiconductors.…”

Section: Introductionmentioning

confidence: 99%

Study of the effect of thermal annealing on the optical and electrical properties of vacuum evaporated amorphous thin films in the system Ge₂₀Te_80-xBi_x

Bhatia

Kishore

Malik

et al. 2002

Semicond. Sci. Technol.

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We systematically studied the effect of thermal annealing on the optical and electrical properties of amorphous semiconducting thin films in the system Ge 20 Te 80−x Bi x (x = 0, 0.19, 2.93, 7.35) prepared by flash evaporation in a vacuum of 1 × 10 −6 Torr. The films are characterized by x-ray diffraction (XRD) and electron probe micro analysis. The annealing temperature is kept at 150 • C, 180 • C and 220 • C. No crystallization of the thin films is achieved on annealing up to the temperature of 150 • C. At a higher temperature of annealing, microcrystals of Te, Bi 2 Te 3 , Ge-Te, etc, are observed along with an amorphous phase as indicated by XRD analysis. The fundamental optical absorption edge and reflection spectra of as-prepared and annealed films are determined. Optical interband transitions are observed for various films (as-prepared and annealed). The presence of crystalline Bi 2 Te 3 in films annealed at 220 • C is also supported by the reflection spectrum. The optical energy gap (E g ), the slope parameter ( ) of the absorption edge and the tailing parameter (B −1 ) of the energy band tails are computed from the optical data. The dc electrical conductivity (σ dc ) of various films is studied in the temperature range of 150-450 K. We observe that two types of conduction take place: conduction through extended states in the higher temperature region, and conduction through localized states in the band tails and at the Fermi level by the hopping process assisted by phonons at lower temperatures. The data at higher temperatures have been fitted with the expression σ dc = σ 0 exp(− E/kT ) and the electrical parameters, E and σ 0 , are also determined. It is observed that the bismuth concentration and annealing temperature dependences of the optical and electrical parameters are different in the two regions of compositions, x 2.93 and x > 2.93, indicating structural differences in the two sets of compositions. It is pointed out that the bulk form of these amorphous semiconductors exhibits a carrier sign reversal at a bismuth concentration of about 3.5 at%. However, the thin-film form of these amorphous semiconductors does not show such a carrier sign reversal in the electrical transport.

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“…It has been found that Se based alloys are more useful, due to their grater hardness, high photosensitivity, higher crystallization temperature and smaller aging effect as compared to pure Se [7]. The crystallization of the binary Se 1 − x Bi x alloys has already been studied by different workers [8][9][10][11][12], who have determined the crystallization parameters by means of conductivity. Several workers have added different elements to the binary Se\Bi system [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…The crystallization of the binary Se 1 − x Bi x alloys has already been studied by different workers [8][9][10][11][12], who have determined the crystallization parameters by means of conductivity. Several workers have added different elements to the binary Se\Bi system [9][10][11]. Several workers have studied the crystallization of ternary Se\Bi\Te glasses [13,14].…”

Section: Introductionmentioning

confidence: 99%

Glass transition and crystallization study of Te additive Se Bi chalcogenide glass

Farid

Atyia

2015

Journal of Non-Crystalline Solids

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Electronic conduction in Bi‐modified amorphous thin films of Ge₂₀Te_80‐xBi_x exhibiting an absence of a p‐n transition

Cited by 12 publications

References 12 publications

Alternating-current conductivity and dielectric properties of Ge₂₅Sb_15-xBi_xS₆₀bulk and thin-film glasses

Alternating-current conductivity and dielectric properties of Ge₂₅Sb_15-xBi_xS₆₀bulk and thin-film glasses

Study of the effect of thermal annealing on the optical and electrical properties of vacuum evaporated amorphous thin films in the system Ge₂₀Te_80-xBi_x

Glass transition and crystallization study of Te additive Se Bi chalcogenide glass

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Electronic conduction in Bi‐modified amorphous thin films of Ge20Te80‐x Bi x exhibiting an absence of a p‐n transition

Cited by 12 publications

References 12 publications

Alternating-current conductivity and dielectric properties of Ge25Sb15-xBixS60bulk and thin-film glasses

Alternating-current conductivity and dielectric properties of Ge25Sb15-xBixS60bulk and thin-film glasses

Study of the effect of thermal annealing on the optical and electrical properties of vacuum evaporated amorphous thin films in the system Ge20Te80-xBix

Glass transition and crystallization study of Te additive Se Bi chalcogenide glass

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Electronic conduction in Bi‐modified amorphous thin films of Ge₂₀Te_80‐xBi_x exhibiting an absence of a p‐n transition

Alternating-current conductivity and dielectric properties of Ge₂₅Sb_15-xBi_xS₆₀bulk and thin-film glasses

Alternating-current conductivity and dielectric properties of Ge₂₅Sb_15-xBi_xS₆₀bulk and thin-film glasses

Study of the effect of thermal annealing on the optical and electrical properties of vacuum evaporated amorphous thin films in the system Ge₂₀Te_80-xBi_x