The Influence of Thermal Disorder on the Absorption Edge in the Tauc Region of a–Si:H

Bindemann, R.; Paetzold, O. H.

doi:10.1002/pssb.2221600252

Cited by 15 publications

(5 citation statements)

References 10 publications

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“…Equation ͑1͒ is valid for a number of amorphous materials in the spectral region of large ␣ ͑10 4 Ͻ ␣ Ͻ 10 5 ͒, i.e., Tauc region. 2,3,13 In the special case where both the conduction and valence band edges have a parabolic shape, the value of p is 2. This quadratic dependence was observed in many chalcogenide glasses like As 2 S 3 , As 2 Se 3 , As 2 Te 3 , etc., 14 but not all chalcogenide glasses.…”

Section: Resultsmentioning

confidence: 99%

Kinetics and chemical analysis of photoinduced interdiffusion in nanolayered Se/As2S3 films

Adarsh

Naik

Sangunni

et al. 2008

Journal of Applied Physics

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We have studied the kinetics of photoinduced effects in nanolayered Se/ As 2 S 3 film by in situ optical absorption measurements, which reveal that photodarkening in these films is followed by photoinduced diffusion. An increase in disorder during photodarkening and its subsequent decrease during photoinduced diffusion were also observed. The observation of photodarkening of Se at room temperature when confined between As 2 S 3 layers suggests that the glass transition temperature of Se shifts to higher energy. The analysis shows that the atoms which take part in photodarkening play a vital role in photoinduced diffusion. The x-ray photoelectron spectroscopy measurements show the atomic movements during photoinduced diffusion. It also shows that some of the As-S bonds are converted into As-Se bonds. Since it is energetically difficult to break an As-S bond to form an As-Se bond, we assume that the new bond formations are taking place by the bond rearrangement mechanism.

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Section: Resultsmentioning

confidence: 99%

Kinetics and chemical analysis of photoinduced interdiffusion in nanolayered Se/As2S3 films

Adarsh

Naik

Sangunni

et al. 2008

Journal of Applied Physics

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“…High values of the exponential absorption edge energy width w (above 100 meV) are typical for glassy semiconductors [22]. Perhaps at T > T c certain "glassy behavior" occurs resulting in the sharp absorption edge broadening due to strong EPI and the smeared tails of the density of electronic states in the gap [23].…”

Section: Temperature and Structural Disordering Effects Upon The Absomentioning

confidence: 99%

Disordering effect on optical absorption processes in CuInP₂S₆ layered ferrielectrics

Studenyak

Mitrovcij

Kovács

et al. 2003

Physica Status Solidi (b)

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The optical absorption edge of CuInP 2 S 6 crystals is studied between 77 and 573 K. The nature of optical transitions, resulting in absorption edge formation in ferrielectric and paraelectric phases, is elucidated. The temperature variation of the energy gap in the ferrielectric phase transition range and the temperature behavior of the Urbach absorption edge in the paraelectric phase are studied. The effect of temperature and structural disordering on the absorption edge energy position and shape is analyzed.

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“…Equation ͑5͒ is valid for a number of amorphous materials in the spectral region of large ␣ ͑10 4 Ͻ ␣ Ͻ 10 5 ͒, i.e., Tauc region. 12,28 Se well layers determine the optical band gap in our AMLs and the band gap values are given in Table I. The optical band gap of ML1 is less than the optical band gap of ML2.…”

Section: Resultsmentioning

confidence: 96%

Photoinduced interdiffusion in nanolayered Se∕As2S3 films: Optical and x-ray photoelectron spectroscopic studies

Adarsh

Sangunni

Shripathi

et al. 2006

Journal of Applied Physics

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Photoinduced interdiffusion was observed with above band gap light in nanolayered Se/ As 2 S 3 films. It is discussed in terms of the optical parameters such as band gap, Urbach edge ͑E e ͒ ͓F. Urbach, Phys. Rev. 92, 1324 ͑1953͔͒, and B 1/2 ͑Tauc's parameter͒ ͓J. Tauc et al., Phys. Status Solidi 15, 627 ͑1966͔͒. Experimental data of B 1/2 and E e for as-prepared samples do not show clear correlation implied by the Mott-Davis model ͓N. F. Mott and E. A. Davis, Electronic Process in Non-crystalline Materials ͑Clarendon, Oxford 1979͒, p. 287͔. It is also shown that the optical parameters can be changed with a change in the Se sublayer thickness. Variations of these optical parameters as a function of modulation period and photoinduced interdiffusion were discussed in terms of the quantum confinement effect and changes in the valence and conduction bands. We proposed a model to explain the mechanism of Se diffusion in As 2 S 3 , which suggests that diffusion takes place through the wrong bonds. X-ray photoelectron spectroscopy ͑XPS͒ is used to investigate the chemical alternations in the bonding. The proposed model was supported by the XPS data.

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The Influence of Thermal Disorder on the Absorption Edge in the Tauc Region of a–Si:H

Cited by 15 publications

References 10 publications

Kinetics and chemical analysis of photoinduced interdiffusion in nanolayered Se/As2S3 films

Kinetics and chemical analysis of photoinduced interdiffusion in nanolayered Se/As2S3 films

Disordering effect on optical absorption processes in CuInP₂S₆ layered ferrielectrics

Photoinduced interdiffusion in nanolayered Se∕As2S3 films: Optical and x-ray photoelectron spectroscopic studies

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The Influence of Thermal Disorder on the Absorption Edge in the Tauc Region of a–Si:H

Cited by 15 publications

References 10 publications

Kinetics and chemical analysis of photoinduced interdiffusion in nanolayered Se/As2S3 films

Kinetics and chemical analysis of photoinduced interdiffusion in nanolayered Se/As2S3 films

Disordering effect on optical absorption processes in CuInP2S6 layered ferrielectrics

Photoinduced interdiffusion in nanolayered Se∕As2S3 films: Optical and x-ray photoelectron spectroscopic studies

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Disordering effect on optical absorption processes in CuInP₂S₆ layered ferrielectrics