Temperature Dependence of the Minority-Carrier Mobility-Lifetime Product for Probing Band-Tail States in Microcrystalline Silicon

Brüggemann, R.; Kunz, Oliver

doi:10.1002/1521-3951(200212)234:3<r16::aid-pssb999916>3.0.co;2-6

Cited by 9 publications

(4 citation statements)

References 17 publications

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“…Bandtail states have previously been proposed to account for electron paramagnetic resonance spectra, 14,15 for photocarrier recombination experiments, 16 and transient photoconductivity measurements 17 in c-Si. One paperreporting temperature-dependent ambipolar diffusion lengths 16 -estimates an exponential valence bandtail width of 26 meV, which seems reasonably consistent with the estimates of 31-32 meV in the present work. These valence bandtail widths for c-Si: H are substantially lower than those ͑40-50 meV͒ reported for a-Si: H. 9,10 While this seems unsurprising, these valence bandtails are actually wider than conduction bandtails ͑20-25 meV͒ in a-Si: H. 18 In this context, it may be useful to make one observation regarding the microscopic character of bandtail states in c -Si: H. Theoretical studies of bandtail states near a mobility edge, such as those probed by drift-mobility measurements, show that these states are not strongly localized on a defective configuration of a few atoms, but are spread over a broad region 13 and possibly with an intricate "spongelike" spatial structure.…”

Section: Hole Drift-mobility Measurements In Microcrystalline Siliconmentioning

confidence: 70%

“…The bandtail multiple-trapping model appears to account well for the temporal and thermal variations of the hole displacement. Bandtail states have previously been proposed to account for electron paramagnetic resonance spectra, 14,15 for photocarrier recombination experiments, 16 and transient photoconductivity measurements 17 in c-Si. One paperreporting temperature-dependent ambipolar diffusion lengths 16 -estimates an exponential valence bandtail width of 26 meV, which seems reasonably consistent with the estimates of 31-32 meV in the present work.…”

Section: Hole Drift-mobility Measurements In Microcrystalline Siliconmentioning

confidence: 99%

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Hole drift-mobility measurements in microcrystalline silicon

Dylla

Finger

Schiff

2005

Applied Physics Letters

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We have measured transient photocurrents on several p-i-n solar cells based on microcrystalline silicon. For two of these samples, we were able to obtain conclusive hole drift-mobility measurements. Despite the predominant crystallinity of these samples, temperature-dependent measurements were consistent with an exponential-bandtail trapping model for transport, which is usually associated with noncrystalline materials. We estimated valence bandtail widths of about 31meV and hole band mobilities of 1–2cm2∕Vs. The measurements support mobility-edge transport for holes in these microcrystalline materials, and broaden the range of materials for which mobility-edge transport corresponds to an apparently universal band mobility of order 1cm2∕Vs.

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Section: Hole Drift-mobility Measurements In Microcrystalline Siliconmentioning

confidence: 70%

Section: Hole Drift-mobility Measurements In Microcrystalline Siliconmentioning

confidence: 99%

Hole drift-mobility measurements in microcrystalline silicon

Dylla

Finger

Schiff

2005

Applied Physics Letters

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“…The value (µτ = 3.3 × 10 −3 cm 2 /V) in monocrystalline diamonds was 2−3 orders of magnitude greater than that in polycrystalline diamonds affected by carrier trapping at grain boundaries. This result indicates the high potential of monocrystalline diamonds among other candidate materials, such as high-purity germanium, microcrystalline silicon 15 , CdZnTe 16 , metal halide perovskites 17 , and h-BN 18 . However, the charge collection method returns the product of µ and τ , and these two parameters are not separable.…”

mentioning

confidence: 87%

Low-temperature mobility-lifetime product in synthetic diamond

Konishi

Akimoto

Matsuoka

et al. 2020

Applied Physics Letters

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Mobility-lifetime (µτ ) product is an important parameter that determines the performance of electronic and photonic devices. To overcome the previously reported difficulties in measuring the µτ product at cryogenic temperatures, we implement a time-resolved cyclotron resonance method to determine the carrier lifetime τ . After clarifying the difference between the AC and DC mobilities measured by the cyclotron resonance and time-of-flight methods, respectively, we demonstrate an inverse temperature dependence of the µτ product. The highest recorded µτ product of 0.2 cm 2 /V, which is approximately 100 times the room-temperature value, was obtained at 2 K for chemical-vapor-deposition diamond of the highest currently available purity.

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“…The T dependence of (mt) p of mc-Si:H was studied by Br€ uggemann and Kunz [60], and also by Balberg [61]. For the analysis, they also performed numerical simulations in order to correlate the experimental and simulation results.…”

Section: Hydrogenated Microcrystalline Siliconmentioning

confidence: 99%

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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Temperature Dependence of the Minority-Carrier Mobility-Lifetime Product for Probing Band-Tail States in Microcrystalline Silicon

Cited by 9 publications

References 17 publications

Hole drift-mobility measurements in microcrystalline silicon

Hole drift-mobility measurements in microcrystalline silicon

Low-temperature mobility-lifetime product in synthetic diamond

Steady‐State Photocarrier Grating Method

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