Effects of proton irradiation on the photoelectronic properties of microcrystalline silicon

Brüggemann, R.; Brehme, S.; Kleider, Jean‐Paul; Gueunier, Marie‐Estelle; Bronner, W.

doi:10.1016/j.jnoncrysol.2004.03.023

Cited by 7 publications

(3 citation statements)

References 17 publications

(19 reference statements)

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“…The fits to the measurements show a reasonable to excellent value of γ 0 , indicating a high quality of the optical grating in the films as well as the suitability of the technique to characterise the selection of materials. For the three silicon‐based materials, the diffusion length values are in agreement with previous work .…”

Section: Resultssupporting

confidence: 90%

Benchmarking photoactive thin‐film materials using a laser‐induced steady‐state photocarrier grating

Veldhuizen

Adhyaksa

Theelen

et al. 2017

Progress in Photovoltaics

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In this study, we assess the charge carrier diffusive transport quality of traditional and emerging thin-film photoactive absorber materials used for photovoltaic applications. We use a steady-state photocarrier grating technique, which has so far been predominantly used for amorphous silicon-based materials, to obtain ambipolar diffusion lengths as well as minority and majority carrier mobility-lifetime products. The measurements are performed at volume-averaged generation rates of G = 10 20 -10 21 cm À3 s À1 and low electric field strengths of E = 20-200 V cm À1 . The absorbing capability of the materials is analysed by calculating an effective optical absorption depth, and we compare its value with the obtained electronic ambipolar diffusion length. The effective absorption depths are independent of the band-gap values so that our assessment is also relevant for multijunction solar cells. We observe that for silicon-based thin-film materials, the ambipolar diffusion length (with a value lower than 150 nm) is more than twice as short as their effective absorption depth, while for copper indium gallium selenide chalcopyrite and halide perovskite materials, the diffusion length (with a value up to 367 nm) is similar or larger than the effective absorption depth. The presented method can be used as a rapid assessment of the optoelectronic quality of photoactive thin-film materials.

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Section: Resultssupporting

confidence: 90%

Benchmarking photoactive thin‐film materials using a laser‐induced steady‐state photocarrier grating

Veldhuizen

Adhyaksa

Theelen

et al. 2017

Progress in Photovoltaics

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“…In the case of light soaking, the light-induced structural damage is negligible due to the low-energy photons, only breaking Si-H bonds and weak Si-Si bonds. This is possibly why Brüggemann et al [11][12][13] observed a decrease in dark conductivity after electron and proton irradiation in undoped hydrogenated microcrystalline silicon which was normally stable against conventional light soaking. As we know, both the dangling-bond defects and the structural order in a-Si : H films affect the electronic transport properties.…”

Section: Resultsmentioning

confidence: 99%

“…Due to the high-energy particles injected into the films giving rise to electronic excitations in the energy band, some groups reported the electron irradiation-induced degradation in electronic conductivity of undoped a-Si : H films [9,10]. Other groups also reported significant degradation under highenergy particle irradiation in undoped microcrystalline silicon, while almost no effect was observed in doped microcrystalline silicon [11][12][13]. The high-energy particle irradiation effects on the properties of heavily doped a-Si : H films are still unclear.…”

Section: Introductionmentioning

confidence: 99%

Electron irradiation effects on the properties of heavily phosphorus-doped a-Si : H films prepared from undiluted silane

Liao¹,

Li²,

Jiang³

et al. 2008

J. Phys. D: Appl. Phys.

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The effects of 1.0 MeV electron irradiation on the dark conductivity and amorphous network of heavily phosphorus-doped a-Si : H films have been studied. The electron irradiation leads to a strong decrease by about two orders of magnitude in the dark conductivity of heavily phosphorus-doped a-Si : H films and the degradation comes to a saturation. The evolutions of the amorphous silicon network of heavily doped a-Si : H films caused by electron irradiation were investigated by Raman spectroscopy. The observed decrease in the amorphous silicon network order in the short and intermediate range suggests that the electron irradiation induces structural defects in the films. This defect creation also tends to saturate after a long irradiation time.

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Steady‐State Photocarrier Grating Method

Brüggemann

2011

Advanced Characterization Techniques for Thin Film Solar Cells

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The excess-carrier properties of a photoexcited semiconductor are important indicators of its quality with respect to applications in optoelectronic devices or for studying the recombination physics. In contrast to the majority-carrier properties, which can be determined rather straightforwardly by stationary photocurrent measurements, the minority-carrier properties can only be revealed by more sophisticated methods. In this respect the steady-state photocarrier grating (SSPG) method has had an enormous impact since it was suggested by Ritter, Zeldov, and Weiser, named RZW hereafter, in 1986 [1].The SSPG method is based on the carrier diffusion under the presence of a spatial sinusoidal modulation in the photogeneration rate G, which induces a so-called photocarrier grating. From photocurrent measurements at different grating periods L, the ambipolar diffusion lengthL can be determined by an analysis that assumes ambipolar transport and charge neutrality.The proposal by RZW, following papers on the analysis [2, 3] and the simple setup triggered a rapid widespread application [4][5][6][7][8]. In parallel, critical and more in-depth accounts on the underlying theory were given to put the technique on a firm ground or to describe its limits when applied to semiconductors with traps. Ritter et al. [9], Balberg et al. [10, 11], Li [12], and Shah et al. [13] analyzed the transport equations, also with respect to the lifetime or relaxation time regimes. In the lifetime regime, the carrier lifetimes are longer than the dielectric relaxation time. The previous publications were later criticized by Hattori et al. [14] who performed a second-order perturbation approach and pointed out deficiencies of other earlier analyses. Nevertheless, Hattori et al. showed that under the conditions in the lifetime regime the analysis and evaluation of the SSPG method are correct. These authors also suggested a correction method to avoid incorrect values of L.A novel aspect was introduced by Abel and Bauer [15] who numerically solved the transport and Poisson equations and compared the solutions with a generalized theory which enables to study the SSPG results by the variation of L and/or electric j177 field E. These authors derive their expressions in terms of the mobility-lifetime product ðmtÞ min of the minority carriers, which can be determined from the SSPG method and related to L.More recently, Schmidt and Longeaud [16] developed a generalized derivation of the solution of the SSPG equations at low E. They identified the shortcomings in the previous derivations which differ from the numerical solution. Their approach also allows the SSPG experiment to be used for the density-of-states (DOS) determination.An important aspect is the above-mentioned association of L with the ðmtÞ min product of the minority carriers. Together with the majority-carrier mobility-lifetime product ðmtÞ maj at the same G from the photoconductivity s ph via s ph ¼ eGðmtÞ maj , where e equals 1.6 Â 10 À19 C, the excess-carrier properties can be related to e...

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Effects of proton irradiation on the photoelectronic properties of microcrystalline silicon

Cited by 7 publications

References 17 publications

Benchmarking photoactive thin‐film materials using a laser‐induced steady‐state photocarrier grating

Benchmarking photoactive thin‐film materials using a laser‐induced steady‐state photocarrier grating

Electron irradiation effects on the properties of heavily phosphorus-doped a-Si : H films prepared from undiluted silane

Steady‐State Photocarrier Grating Method

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