Errors introduced in a-Si:H-based solar cell modeling when dangling bonds are approximated by decoupled states

Klimovsky, E.; Rath, J.K.; Schropp, R.E.I.; Rubinelli, Francisco Alberto

doi:10.1016/s0040-6090(02)00972-0

Cited by 11 publications

(20 citation statements)

References 8 publications

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“…Three amphoteric-like Gaussians, D + , D 0 , and D − , were adopted to model the density of mid-gap states in the nc-Si:H layers. 15 The areas, widths, and heights of the Gaussians are shown in Table I. The dangling bond ͑DB͒ densities adopted in doped layers are based on experimental results and on typical values extracted from the literature.…”

Section: B Input Parameters For D-ampsmentioning

confidence: 99%

Photogating effect as a defect probe in hydrogenated nanocrystalline silicon solar cells

Schropp¹,

Rubinelli²

2010

Journal of Applied Physics

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The measurement of the spectrally resolved collection efficiency is of great importance in solar cell characterization. Under standard conditions the bias light is a solar simulator or a light source with a similar broadband irradiation spectrum. When a colored blue or red bias light is used instead, an enhanced collection efficiency effect, in the literature known as the photogating effect, can be observed under certain conditions. While most of the published reports on such effect were on solar cells with amorphous silicon based absorber layers, we have shown that the enhanced collection efficiency could be also present in thin film silicon solar cells where hydrogenated nanocrystalline silicon ͑nc-Si:H͒ is used as the absorber layer. In this article we present detailed experimental results and simulations aiming at a better understanding of this phenomenon. We show that the collection efficiency is strongly dependent on the intensity of bias light and the intensity of the monochromatic light. These experimental results are consistent with the computer predictions made by our code. We also show that the photogating effect is greatly enhanced when nanocrystalline silicon cells are built with an improperly doped p-layer or with a defective p/i interface region due to the reduced internal electric field present in such cells. The existence of this effect further proves that carrier transport in a nc-Si:H solar cell with an i-layer made close to the phase transition regime is influenced to a large extent by drift transport. The study of this effect is proposed as an alternative approach to gain a deeper understanding about the carrier transport scenarios in thin film solar cells, especially nanocrystalline silicon solar cells.

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Section: B Input Parameters For D-ampsmentioning

confidence: 99%

Photogating effect as a defect probe in hydrogenated nanocrystalline silicon solar cells

Schropp¹,

Rubinelli²

2010

Journal of Applied Physics

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“…, and D þ , which in this paper are approximated by three pairs of Gaussians with donor-like and acceptor-like states separated in energy by U þ 2kTln(2). 3 The rich structure of traps present in the mobility gap makes the performance of a-Si:H based electronic devices highly dependent on the DOS. The electric field, that separates the photo-generated free carriers in the intrinsic layers of single and multiple p-i-n junctions, could be weakened by carrier trapping at gap states that, in turn, would give rise to an increase of the recombination rate and to a reduction of the collected carriers at external contacts.…”

Section: Introductionmentioning

confidence: 99%

Impact of implementing the Meyer-Neldel behavior of carrier emission pre-factors in solar cell and optical detector modeling

Rubinelli

Ramirez

2015

Journal of Applied Physics

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Articles you may be interested in A study of quantum well solar cell structures with bound-to-continuum transitions for reduced carrier recombination Appl. Phys. Lett. 102, 213903 (2013) The Meyer-Neldel behavior reported for the emission probabilities of electrons and holes was included in our code, replacing the gap state capture cross sections of the Shockley-Read-Hall formalisms with capture cross sections containing an exponential function of the trap energy depth. The Meyer-Neldel energies for electrons and holes are the slopes of these exponentials. Our results indicate that emission probabilities of neutral states no deeper than approximately 0.45 eV and 0.37 eV from the conduction and valence band edges, respectively, can show a Meyer-Neldel behavior only, while on the other hand, its implementation in deeper gap states makes the replication of experimental J-V curves of p-i-n solar cells and detectors impossible. The Meyer-Neldel behavior can be included in all neutral capture cross sections of acceptor-like tail states without affecting the J-V characteristics, while it cannot be included in all capture cross sections of neutral donor-like tail states and/or defect states without predicting device performances below the experimental figures, that become even lower when it is also included in charged capture cross sections. The implementation of the anti Meyer-Neldel behavior at tail states gives rise to slightly better and reasonable device performances. V C 2015 AIP Publishing LLC.

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“…Figure 2(a) and (b) shows that the most significant contribution to the generation rate in the SRH formalism comes from gap states with energies between E fnt and E fpt , which justifies the limits of integration adopted in Eqs. (12).…”

mentioning

confidence: 99%

“…Replacing Eqs. (3), (7), and (12) in Eq. (13) after some algebra, the following formulas can be derived:…”

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Simplified method for the evaluation of the reverse dark current–voltage characteristic of thin film devices

Rubinelli

Greef

2015

Physica Status Solidi (b)

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An algorithm that simplifies the evaluation of the reverse dark current–voltage (J–V) characteristic of semiconductor thin film devices is presented. This algorithm, recognized with the symbols “0KRDA”, is an approximation of the SRH formalism that can be used when the dangling bond density is modeled with either the Uniform Density Model or with the Defect Pool Model. The 0KRDA is designed to replace the 0K‐Simmons–Taylor approximation (0KSTA) in reversed biased junctions operating under dark conditions. The dependence of the current density J with respect to the applied voltage V predicted with SRH formalism is well replicated by the 0KRDA. The small differences obtained in the calculated reverse dark currents can be removed by neglecting the contribution of gap states with energies closer than kT/5 to the intrinsic trap level. The transport physic controlling the shape of reverse dark J–V curves of thin film devices can be more easily visualized with the 0KRDA.

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Errors introduced in a-Si:H-based solar cell modeling when dangling bonds are approximated by decoupled states

Cited by 11 publications

References 8 publications

Photogating effect as a defect probe in hydrogenated nanocrystalline silicon solar cells

Photogating effect as a defect probe in hydrogenated nanocrystalline silicon solar cells

Impact of implementing the Meyer-Neldel behavior of carrier emission pre-factors in solar cell and optical detector modeling

Simplified method for the evaluation of the reverse dark current–voltage characteristic of thin film devices

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