Study of metastabilities in microcrystalline silicon films by photoconductivity techniques

Souffi, N.; Bauer, G.H.; Brüggemann, R.

doi:10.1016/j.tsf.2005.07.139

Cited by 8 publications

(11 citation statements)

References 12 publications

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“…This result is in agreement with other published reports. 23 The noticeable difference between our results and those reported by Souffi et al 23 is the sharper drop of the photoconductivity for our amorphous film in the first 20 h of illumination. On the other hand, the photocurrent of the two films probed in our investigation stabilised after 200 h of illumination.…”

Section: Resultscontrasting

confidence: 89%

Synthesis of nanocrystalline silicon thin films using the increase of the deposition pressure in the hot-wire chemical vapour deposition technique

Halindintwali¹,

Knoesen²,

Swanepoel³

et al. 2010

S Afr J Sci

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Section: Resultscontrasting

confidence: 89%

Synthesis of nanocrystalline silicon thin films using the increase of the deposition pressure in the hot-wire chemical vapour deposition technique

Halindintwali¹,

Knoesen²,

Swanepoel³

et al. 2010

S Afr J Sci

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“…We can compare our results with those achieved previously for a series of c-Si: H, 82 doped samples of a-Si: H ͑Ref. 73͒ and c-Si: H, 4 or with the degradation of the doped c-Si: H. [83][84][85] In Fig. 4 Fig.…”

Section: E Photoconductivity and Defects In C-si: H Doped With Psupporting

confidence: 52%

“…On the other hand, changes in the photoconductivity due to Fermi-level shift have been reported for a-Si: H ͑Refs. 73-77͒ and c-Si: H. 4,[82][83][84][85] Therefore, the dependence of ph on d is used to evaluate the effect of the defect density on the recombination in doped samples.…”

Section: Conductivity In C-si: H Doped With Pmentioning

confidence: 99%

Relationship between defect density and charge carrier transport in amorphous and microcrystalline silicon

et al. 2009

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The influence of dangling-bond defects and the position of the Fermi level on the charge carrier transport properties in undoped and phosphorous doped thin-film silicon with structure compositions all the way from highly crystalline to amorphous is investigated. The dangling-bond density is varied reproducibly over several orders of magnitude by electron bombardment and subsequent annealing. The defects are investigated by electron-spin-resonance and photoconductivity spectroscopies. Comparing intrinsic amorphous and microcrystalline silicon, it is found that the relationship between defect density and photoconductivity is different in both undoped materials, while a similar strong influence of the position of the Fermi level on photoconductivity via the charge carrier lifetime is found in the doped materials. The latter allows a quantitative determination of the value of the transport gap energy in microcrystalline silicon. The photoconductivity in intrinsic microcrystalline silicon is, on one hand, considerably less affected by the bombardment but, on the other hand, does not generally recover with annealing of the defects and is independent from the spin density which itself can be annealed back to the as-deposited level. For amorphous silicon and material prepared close to the crystalline growth regime, the results for nonequilibrium transport fit perfectly to a recombination model based on direct capture into neutral dangling bonds over a wide range of defect densities. For the heterogeneous microcrystalline silicon, this model fails completely. The application of photoconductivity spectroscopy in the constant photocurrent mode ͑CPM͒ is explored for the entire structure composition range over a wide variation in defect densities. For amorphous silicon previously reported linear correlation between the spin density and the subgap absorption is confirmed for defect densities below 10 18 cm −3 . Beyond this defect level, a sublinear relation is found i.e., not all spin-detected defects are also visible in the CPM spectra. Finally, the evaluation of CPM spectra in defect-rich microcrystalline silicon shows complete absence of any correlation between spindetected defects and subband gap absorption determined from CPM: a result which casts considerable doubt on the usefulness of this technique for the determination of defect densities in microcrystalline silicon. The result can be related to the inhomogeneous structure of microcrystalline silicon with its consequences on transport and recombination processes.

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“…Both reversible and irreversible effects may occur [2,4]. Reversibly adsorbed atmospheric components may be removed, for example, by thermal annealing at temperatures between 100 °C and 160 °C [4][5][6][7]. Depending on microstructure, films can show a conductivity decrease after storage in ambient air (Type I), usually samples with high crystalline volume fraction.…”

mentioning

confidence: 99%

Instability effects in hydrogenated microcrystalline silicon thin films

Yilmaz

Turan

Güneş

et al. 2010

Phys. Status Solidi (c)

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Instability effects on the dark conductivity (σDark) and photoconductivity (σphoto) of microcrystalline silicon films with different microstructures deposited on smooth and rough substrates, after exposure to different storage conditions have been investigated. Samples stored in vacuum are less affected by aging than films stored in air and sealed plastic bags filled with N2 gas. The aging is reversible after annealing at 450 K. Thin films deposited on smooth and rough substrates with the same thickness and silane concentrations (SC) during the same deposition run showed similar aging effects. Thick samples exhibited a decrease in σDark, while both decrease and increase in σDark occur in thin samples after aging. For each sample, σDark and σphoto presented the same type of aging, independent of thickness and type of substrate used. The applicability of the steady‐state photocarrier grating technique was successfully tested on the rough substrates. Light‐induced degradation studies confirm the dependence of the Staebler‐Wronski effect on the crystallinity of the material (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Study of metastabilities in microcrystalline silicon films by photoconductivity techniques

Cited by 8 publications

References 12 publications

Synthesis of nanocrystalline silicon thin films using the increase of the deposition pressure in the hot-wire chemical vapour deposition technique

Synthesis of nanocrystalline silicon thin films using the increase of the deposition pressure in the hot-wire chemical vapour deposition technique

Relationship between defect density and charge carrier transport in amorphous and microcrystalline silicon

Instability effects in hydrogenated microcrystalline silicon thin films

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