Are there Charged Dangling Bonds in Device Quality Amorphous Silicon?

Brandt, Martin S.; Asano, A.; Stutzmann, M.

doi:10.1557/proc-297-201

Cited by 12 publications

(6 citation statements)

References 15 publications

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“…It is known that the PDS absorption in the subgap region of intrinsic a-Si:H correlates well with the density of neutral dangling bonds as measured by ESR ( [9] and ref. It is known that the PDS absorption in the subgap region of intrinsic a-Si:H correlates well with the density of neutral dangling bonds as measured by ESR ( [9] and ref.…”

Section: Light-induced Changes In the Electronic Density Of Statessupporting

confidence: 56%

Microscopic Aspects of the Staebler-Wronski Effect

Stutzmann

1997

MRS Proc.

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The microscopic origin and the creation mechanisms of metastable, light-induced defects in hydrogenated amorphous silicon are reviewed. Based on excitonic electron-hole pair recombination, a consistent quantitative description of defect creation kinetics can be obtained, including the experimentally observed differences between continuous wave and pulsed illumination as well as the effect of competing recombination pathways in compensated material. High resolution spin resonance spectra obtained by low-field spin-dependent transport are used to examine the interaction of metastable defects with hydrogen.

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Section: Light-induced Changes In the Electronic Density Of Statessupporting

confidence: 56%

Microscopic Aspects of the Staebler-Wronski Effect

Stutzmann

1997

MRS Proc.

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“…2͒ 12. The dangling bond densities as measured by PDS are rather high in this case as the films used were only 300 nm thick and the measurement is sensitive to the presence of surface states.…”

mentioning

confidence: 91%

Integration of amorphous and polycrystalline silicon thin-film transistors through selective crystallization of amorphous silicon

Pangal

Sturm

Wagner

1999

Applied Physics Letters

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Selective exposure of a hydrogenated amorphous silicon (a-Si:H) film to a room-temperature hydrogen plasma using a patterned masking layer and a subsequent anneal at 600 °C, results in patterned polycrystalline and amorphous silicon regions. However, most of the hydrogen in the amorphous silicon is lost, leading to severe degradation in its properties. In this letter, we report the rehydrogenation of amorphous silicon films following this anneal to give a-Si:H thin-film transistors with a mobility as high as 1.2 cm2/V s and ON/OFF current ratios of ∼106. This process was used to integrate amorphous and polycrystalline silicon transistors on a single substrate with only one more lithography and processing step than that required for a single type of transistor.

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“…This assumption is supported by ESR measurements of the untreated (flat) a-Si:H samples, which show dangling bond densities of about 10 16 cm À3 , corresponding to an optical absorption coefficient at 1.3 eV of a 0 % 10 0 cm À1 . 24 A remarkable alteration of the absorption develops after the black etching treatment of a-Si:H films, as can be seen in Fig. 3(a).…”

Section: B Photothermal Deflection Spectroscopymentioning

confidence: 80%

“…This value corresponds to a defect-related absorption index a(1.3 eV) % 10 1 cm À1 , 24 which is much too low to account for the high optical absorption observed at 1.3 eV, which, if originating from dangling bonds, would correspond to dangling bond densities exceeding 10 18 cm À3 . 24 Similarly, the strong photoconductivity of the samples discussed in Sec. V is at variance with the idea of such large concentrations of defects being the reason for the absorption enhancement.…”

Section: B Photothermal Deflection Spectroscopymentioning

confidence: 97%

Black thin film silicon

Koynov

Brandt

Stutzmann

2011

Journal of Applied Physics

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“Black etching” has been proposed previously as a method for the nanoscale texturing of silicon surfaces, which results in an almost complete suppression of reflectivity in the spectral range of absorption relevant for photovoltaics. The method modifies the topmost 150 to 300 nm of the material and thus also is applicable for thin films of silicon. The present work is focused on the optical effects induced by the black-etching treatment on hydrogenated amorphous and microcrystalline silicon thin films, in particular with respect to their application in solar cells. In addition to a strong reduction of the reflectivity, efficient light trapping within the modified thin films is found. The enhancement of the optical absorption due to the light trapping is investigated via photometric measurements and photothermal deflection spectroscopy. The correlation of the texture morphology (characterized via atomic force microscopy) with the optical effects is discussed in terms of an effective medium with gradually varying optical density and in the framework of the theory of statistical light trapping. Photoconductivity spectra directly show that the light trapping causes a significant prolongation of the light path within the black silicon films by up to 15 μm for ∼1 μm thick films, leading to a significant increase of the absorption in the red.

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Are there Charged Dangling Bonds in Device Quality Amorphous Silicon?

Cited by 12 publications

References 15 publications

Microscopic Aspects of the Staebler-Wronski Effect

Microscopic Aspects of the Staebler-Wronski Effect

Integration of amorphous and polycrystalline silicon thin-film transistors through selective crystallization of amorphous silicon

Black thin film silicon

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