Comparison of AC and DC constant photocurrent methods for determination of defect densities

Main, C.; Reynolds, S.; Zrinscak, I.; Merazga, Amar

doi:10.1016/j.jnoncrysol.2004.02.059

Cited by 18 publications

(11 citation statements)

References 9 publications

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“…The phenomena observed in a-Si:H thin film CPM and FTPS spectra are in good agreement with [7] where results of DC and AC CPM (measured at various chopping frequencies) are compared and differences explained on the basis of theoretical modeling.…”

Section: Discussionsupporting

confidence: 80%

Comparison of photocurrent spectra measured by FTPS and CPM for amorphous silicon layers and solar cells

Holovský

Poruba

Purkrt

et al. 2008

Journal of Non-Crystalline Solids

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Section: Discussionsupporting

confidence: 80%

Comparison of photocurrent spectra measured by FTPS and CPM for amorphous silicon layers and solar cells

Holovský

Poruba

Purkrt

et al. 2008

Journal of Non-Crystalline Solids

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“…53 The application of both CPM and PDS for evaluation of the defect density is established for a-Si: H. Methods to identify the contribution from the defects on the absorption spectra have been investigated and described in detail in the literature. 52,53,[92][93][94][95][96] For c-Si: H the relation between defect absorption measured with PDS and spin density was recently investigated. 62 It was seen that an almost linear relationship between the defect absorption and N s exists over 3 orders of magnitude, but there are also considerable deviations from this behavior which makes use of PDS for optimization difficult.…”

Section: E Photoconductivity and Defects 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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“…It is known that CPM spectra may be influenced by transport and recombination processes. Discrepancies between the absorption spectrum in some of a-Si:H films obtained by DC and AC CPM have been noted by several groups [10][11][12]. The discrepancy is in the 'defect' region of the spectrum, at photon energies below 1.4 eV with the DC technique consistently giving a higher value.…”

Section: Discussionmentioning

confidence: 99%

Peculiarity of constant photocurrent method for silicon films with mixed amorphous–nanocrystalline structure

Казанский

Kong

Zeng

et al. 2008

Journal of Non-Crystalline Solids

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Comparison of AC and DC constant photocurrent methods for determination of defect densities

Cited by 18 publications

References 9 publications

Comparison of photocurrent spectra measured by FTPS and CPM for amorphous silicon layers and solar cells

Comparison of photocurrent spectra measured by FTPS and CPM for amorphous silicon layers and solar cells

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

Peculiarity of constant photocurrent method for silicon films with mixed amorphous–nanocrystalline structure

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