Influence of the broken symmetry of defect state distribution at the a-Si:H/c-Si interface on the performance of hetero-junction solar cells

Mikolášek, Miroslav; Racko, J.; Harmatha, L.; Gaspierik, P.; Šutta, P.

doi:10.1016/j.apsusc.2010.03.023

Cited by 17 publications

(6 citation statements)

References 3 publications

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“…As described in Ref. [21], the doping concentration of the emitter layer will affect the performance of an a-Si:H (n)/c-Si(p) heterojunction solar cell obviously. So, the effect of doping concentration of the emitter layer on the performance of the silicon thin film heterojunction solar cell is also studied here.…”

Section: Resultsmentioning

confidence: 99%

Effect of emitter layer doping concentration on the performance of a silicon thin film heterojunction solar cell

et al. 2013

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A novel type of n/i/i/p heterojunction solar cell with a-Si:H(15 nm)/a-Si:H(10 nm)/ epitaxial c-Si(47 μm)/epitaxial c-Si(3 μm) structure is fabricated by using the layer transfer technique, and the emitter layer is deposited by hot wire chemical vapour deposition. The effect of the doping concentration of the emitter layer Sd (Sd=PH3/(PH3+SiH4+H2)) on the performance of the solar cell is studied by means of current density—voltage and external quantum efficiency. The results show that the conversion efficiency of the solar cell first increases to a maximum value and then decreases with Sd increasing from 0.1% to 0.4%. The best performance of the solar cell is obtained at Sd = 0.2% with an open circuit voltage of 534 mV, a short circuit current density of 23.35 mA/cm2, a fill factor of 63.3%, and a conversion efficiency of 7.9%.

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Section: Resultsmentioning

confidence: 99%

Effect of emitter layer doping concentration on the performance of a silicon thin film heterojunction solar cell

et al. 2013

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“…The thin film PEC photocathodes were prepared with following layer sequence: Glass-ITO/a-SiC:H(p) 50nm ASA simulation software [16] was used for simulation of light I − V curves of solar cells. Input parameters for SHJ model used during the simulation were adopted from [17,18]. The incident solar spectrum used in ASA for estimation of PEC-PV efficiency was calculated by considering the transmittance of PEC samples and solar spectrum.…”

Section: Methodsmentioning

confidence: 99%

Amorphous silicon PEC-PV hybrid structure for photo-electrochemical water splitting

Mikolášek

Kemeny

Chymo

et al. 2019

Journal of Electrical Engineering

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The paper presents fabrication and characterization of amorphous silicon carbide (a-SiC:H) based structures for photo-electrochemical (PEC) water splitting. The increase of the photocurrent of PEC upon the decreased of CH4 flow during the deposition is associated with the decrease of the band gap and increased absorption of light in a-SiC:H. Photocurrent of 50 µA/cm2 is achieved for PEC structure prepared with the lowest CH4 flow during the deposition. An ITO/a-SiC:H/Si silicon heterojunction structure forming a simple photovoltaic cell (PV) with efficiency of 9.66% was prepared to support additional voltage hereby forming a hybrid PEC-PV system. ASA simulation revealed that a photocurrent of 0.62 mA/cm2 and solar to hydrogen efficiency of 0.76% can be achieved for hybrid a PEC-PV structure with 5 PVs connected in series behind the PEC cell. Further opportunities for increasing the performance are discussed and summarized.

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“…To understand the impact of such trap states on photoanodes, we shall utilize a semiclassical model describing the trapping/detrapping dynamics of intermediate band-gap states. The approach we employ was originally developed to understand the operation of solid-state semiconductor devices prone to trapping. ,, A particular example would be the simulation of silicon heterojunction solar cells. − Now, Figure presents a generic picture of carrier trapping/detrapping events by intermediate states. Here, we show trap states with both acceptor and donor characteristics inside a band gap.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, the total charge contribution from a distribution of acceptor states is ,, Similarly, the concentration of holes captured by a donor state located at energy E , position x , and electrostatic potential ϕ is given by , and the total charge provided by the distribution of donor states is expressed as Finally, the net charge contribution from the distribution of bulk trap states of both acceptor and donor type is computed as In our analysis of ρ T , we have approximated g T|A and g T|D to take a normal distribution with respect to energy (see Figure ), following state-of-the-art modeling efforts regarding trap states inside disordered semiconductors by the device physics community (e.g., amorphous silicon). − For instance, in our computation, g T|A is given by here, E T|A and W T|A /√2, respectively, are the location of the peak and the standard deviation of the distribution in electron volts, and Ñ T|A is the total number of acceptor-type trap states in the band gap in cm –3 . Importantly, a normal distribution conserves the total number of states ( Ñ T|A ) even when the peak location and spread are altered.…”

Section: Methodsmentioning

confidence: 99%

Impact of Bulk Trapping Phenomena on the Maximum Attainable Photovoltage of Semiconductor–Liquid Interfaces

et al. 2018

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In this work, we present a generic semiclassical approach for theoretically evaluating the impact of bulk trap states on the maximum attainable photovoltage in solar-assisted water-splitting reactions. Our method explicitly considers the charge contribution due to the capture and emission of conduction band electrons and valence band holes by trap states situated in the band gap, integrated within a self-consistent solution procedure for calculating electrostatic and charge transport properties. Utilizing the hematite photoanode as our model system, our approach reveals that bulk trap states may significantly degrade both the maximum attainable photovoltage and the concentration of mobile electrons (majority carriers) in the conduction band. These results suggest that bulk trap states can have two primary consequences in photoanodes. First, they may limit the degree to which a favorable cathodic shift in the photocurrent can be achieved (by lowering the maximum attainable photovoltage). Second, they may impede the extraction of majority carriers at the bulk-electrode contact (by lowering the conduction band carrier concentration). Both of these phenomena are commonly observed in the state-of-the-art hematite photoanodes. Our semiclassical analysis is further supported by first-principles calculations of hematite, which suggest that electron polarons impact adversely upon the maximum attainable photovoltage of oxide photoanodes. In general, this work underscores the importance of engineering the bulk electronic properties of photoelectrodes and is intended to further assist the design of photoanodes en route to low-cost unassisted solar-water splitting.

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Influence of the broken symmetry of defect state distribution at the a-Si:H/c-Si interface on the performance of hetero-junction solar cells

Cited by 17 publications

References 3 publications

Effect of emitter layer doping concentration on the performance of a silicon thin film heterojunction solar cell

Effect of emitter layer doping concentration on the performance of a silicon thin film heterojunction solar cell

Amorphous silicon PEC-PV hybrid structure for photo-electrochemical water splitting

Impact of Bulk Trapping Phenomena on the Maximum Attainable Photovoltage of Semiconductor–Liquid Interfaces

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