Correlation between the results of charge deep-level transient spectroscopy and ESR techniques for undoped hydrogenated amorphous silicon

Nádaždy, Vojtěch; Durń, R.; Thurzo, I.; Pinčík, Emil; Nishida, Akihiko; Shimizu, Junichi; Kumeda, Minoru; Shimizu, Tatsuo

doi:10.1103/physrevb.66.195211

Cited by 21 publications

(18 citation statements)

References 26 publications

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“…Similarly, the calculated steady state occupied and unoccupied integrated densities of D d (E) are found to be equal to the introduced integrated densities of the negative and neutral dangling bonds, respectively. Moreover, the free-carrier densities calculated by means of the charge-neutrality condition for the amphoteric dangling bonds (D + (E), D 0 (E) and D − (E)) are found to be equal with those calculated by replacing the dangling bonds with the monovalent D a (E) and D d (E) obtained from Equations (8) and (9). Therefore, the D a (E) and D d (E) can successfully replace the amphoteric dangling bonds to treat them exactly in the model simulations.…”

Section: Incorporation Of Amphoteric States For the Dangling Bondsmentioning

confidence: 99%

“…Figures 8(b) and (c) present the D + (E), D 0 (E) and D − (E) distributions calculated for the two free-carrier densities n = 1 × 10 9 and 7 Â 10 9 cm À3 , respectively, which are used for the reconstruction of the experimental spectra of Figure 10 obtained with two different bias light levels. From the above distributions the D a (E) and D d (E) are calculated by means of Equations (8) and (9), which in fact represent the D +/0 and D 0/− levels, respectively. These two transition levels are plotted in Figure 9 (solid and dashed-dotted lines).…”

Section: Reconstruction Of the Experimental Mpc Spectramentioning

confidence: 99%

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Determination of trapping–detrapping events, recombination processes and gap-state parameters by modulated photocurrent measurements on amorphous silicon

Pomoni

Kounavis

2014

Philosophical Magazine

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Analysis of the out-of-phase modulated photocurrent (MPC) signal, the so-called Y signal, is proposed for determining the trapping-detrapping events, recombination processes and gap-state parameters in amorphous silicon. This is demonstrated by analysing experimental Y spectra obtained on this material from different laboratories including our own. Model simulations are also employed in which the amphoteric nature of the dangling bonds and their distribution according to the defect-pool model are taken into account. From the reconstruction of the Y signal, phase shift and MPC amplitude spectra, several contributions resolved from the frequency dependence of the experimental Y spectra are identified. Two electron trappingdetrapping processes are resolved. These are attributed to hydrogen-related positive defects and to transitions involving the D +/0 level of the normal dangling bonds from the defect-pool distribution. At lower frequencies a residual contribution is resolved that is attributed to a term related to recombination through the D +/0 and D 0/− levels. Between 300 and 150 K the above recombination contribution is essentially from the D 0/− and dominates the Y signal at lower frequencies. In this region a characteristic phase lead appears, which is attributed to the existence of safe hole traps in the valence band tail. Around 150 K, trapping-detrapping events in the conduction band tail dominate.

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Section: Incorporation Of Amphoteric States For the Dangling Bondsmentioning

confidence: 99%

Section: Reconstruction Of the Experimental Mpc Spectramentioning

confidence: 99%

Determination of trapping–detrapping events, recombination processes and gap-state parameters by modulated photocurrent measurements on amorphous silicon

Pomoni

Kounavis

2014

Philosophical Magazine

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“…On the basis of previous Q-DLTS experiments [6,8] we have claimed that during initial stage of LS a removal rather than creation of positively charged defects positioned well above midgap takes place. The removal of these defects produces the shift of the Fermi level towards midgap and the decay of dark current and photocurrent.…”

Section: Discussionmentioning

confidence: 98%

“…[8]. The Q-DLTS spectrum of the sample annealed at zero bias voltage (intrinsic type of EDOS) was fitted with the EDOS calculated by the defect-pool model from 1996 [5].…”

Section: Experiments and Simulationmentioning

confidence: 99%

Defect-state engineering in a-Si:H: An effective tool for studying processes during light-induced degradation

Nádaždy

Durný

Zeman

2006

Journal of Non-Crystalline Solids

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“…According to the defect-pool model by Powell and Deane, 8 10 Q-DLTS measurements were performed on a-Si: H based metal-oxide-semiconductor ͑MOS͒ structures, consisting of a 1-m-thick a-Si: H layer deposited on n ++ crystalline Si. The fabrication method of the MOS structure is described by Durný et al 11 The measurements were carried out using a bias voltage of −3 V, excitation pulses of 6 V, and a rate window of 100 s −1 .…”

mentioning

confidence: 99%

Charge deep-level transient spectroscopy study of high-energy-electron-beam-irradiated hydrogenated amorphous silicon

Klaver

Nádaždy²,

Zeman

et al. 2006

Applied Physics Letters

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We present a study of changes in the defect density of states in hydrogenated amorphous silicon ͑a-Si: H͒ due to high-energy electron irradiation using charged deep-level transient spectroscopy. It was found that defect states near the conduction band were removed, while in other band gap regions the defect-state density increased. A similar trend is observed for a-Si: H which has been subjected to light soaking, but in that case the majority of defect states are created around midgap, whereas with electron-beam degradation more defect states are created near the valence-band tail. © 2006 American Institute of Physics. ͓DOI: 10.1063/1.2221876͔ Hydrogenated amorphous silicon ͑a-Si: H͒ solar cells show great promise for space application, particularly in high-radiation missions, due to their relatively high radiation tolerance and low-temperature annealing properties. 1,2 Various studies have addressed the degradation behavior of a -Si: H due to high-energy charged particle irradiation, and it is generally accepted that changes in the defect density of states govern the degradation, although trapping of the incident charge on preexisting defects is also considered. [3][4][5] The underlying degradation mechanism, however, is still under debate. Danesh et al.,6 amongst others, showed that there is a strong similarity between high-energy charged particle irradiation and the Staebler-Wronski effect, 7 i.e., reversible changes in electronic properties of a-Si: H under light exposure. In that case, it is expected that the defect-state distribution after light soaking is similar to the distribution after high-energy electron-beam irradiation. In this letter we report on changes in defect-state distribution of a-Si: H due to electron-beam irradiation measured by charge deep-level transient spectroscopy ͑Q-DLTS͒. These results are compared to findings from light-soaking experiments in order to investigate the reported similarities in the defect-creation mechanism further.Q-DLTS has been utilized to study the defect-state distribution in as-deposited as well as in light-soaked a-Si: H. This technique gives direct information about the energy distribution of the gap states and is very sensitive to changes in the gap-state distribution. According to the defect-pool model by Powell and Deane,8 Q-DLTS measurements were performed on a-Si: H based metal-oxide-semiconductor ͑MOS͒ structures, consisting of a 1-m-thick a-Si: H layer deposited on n ++ crystalline Si. The fabrication method of the MOS structure is described by Durný et al. 11 The measurements were carried out using a bias voltage of −3 V, excitation pulses of 6 V, and a rate window of 100 s −1 . Prior to electron-beam irradiation or light soaking, the samples were annealed at 200°C for 30 min. A Van de Graaff accelerator, with a beam current density of 1.5ϫ 10 12 electrons cm −2 s −1 , was employed for the 1-MeV electron irradiation using a fluence of 2 ϫ 10 15 and 2 ϫ 10 16 electrons cm −2 . Light soaking was performed for 6 and 60 min using a red light laser havin...

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Correlation between the results of charge deep-level transient spectroscopy and ESR techniques for undoped hydrogenated amorphous silicon

Cited by 21 publications

References 26 publications

Determination of trapping–detrapping events, recombination processes and gap-state parameters by modulated photocurrent measurements on amorphous silicon

Determination of trapping–detrapping events, recombination processes and gap-state parameters by modulated photocurrent measurements on amorphous silicon

Defect-state engineering in a-Si:H: An effective tool for studying processes during light-induced degradation

Charge deep-level transient spectroscopy study of high-energy-electron-beam-irradiated hydrogenated amorphous silicon

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