Extended infrared response of silicon solar cells and the impurity photovoltaic effect

Keevers, Mark J.; Green, Martin A.

doi:10.1016/0927-0248(95)00113-1

Cited by 56 publications

(34 citation statements)

References 19 publications

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“…3. 30 The calculation of the implanted layer absorption coefficient from transmittance and reflectance measurements is confident up to 1.2 eV, since over this energy absorption in the 300 lm thick substrate predominates. The high absorption of the asimplanted sample has been attributed to the high concentration of defects produced by the implantation process.…”

Section: à3mentioning

confidence: 99%

Ruling out the impact of defects on the below band gap photoconductivity of Ti supersaturated Si

Olea

Pastor

Prado

et al. 2013

Journal of Applied Physics

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In this study, we present a structural and optoelectronic characterization of high dose Ti implanted Si subsequently pulsed-laser melted (Ti supersaturated Si). Time-of-flight secondary ion mass spectrometry analysis reveals that the theoretical Mott limit has been surpassed after the laser process and transmission electron microscopy images show a good lattice reconstruction. Optical characterization shows strong sub-band gap absorption related to the high Ti concentration. Photoconductivity measurements show that Ti supersaturated Si presents spectral response orders of magnitude higher than unimplanted Si at energies below the band gap. We conclude that the observed below band gap photoconductivity cannot be attributed to structural defects produced by the fabrication processes and suggest that both absorption coefficient of the new material and lifetime of photoexcited carriers have been enhanced due to the presence of a high Ti concentration. This remarkable result proves that Ti supersaturated Si is a promising material for both infrared detectors and high efficiency photovoltaic devices. V C 2013 AIP Publishing LLC.

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Section: à3mentioning

confidence: 99%

Ruling out the impact of defects on the below band gap photoconductivity of Ti supersaturated Si

Olea

Pastor

Prado

et al. 2013

Journal of Applied Physics

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“…Si material has advantages of nontoxicity and low-cost. Commercial polycrystalline silicon thin-film solar cells have been fabricated by CSG Solar which achieved photovoltaic conversion efficiency of 10.4% in 2007 [1]. In this solar cell, 2 μm thick a-Si thin-films on borosilicate glass were crystallized using solid phase crystallization (SPC) process which produced grain sizes in the range of 1-2 μm.…”

Section: Introductionmentioning

confidence: 99%

Diode laser crystallization processes of Si thin-film solar cells on glass

et al. 2014

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The crystallization of Si thin-film on glass using continuous-wave diode laser is performed. The effect of various processing parameters including laser power density and scanning speed is investigated in respect to microstructure and crystallographic orientation. Optimal laser power as per scanning speed is required in order to completely melt the entire Si film. When scan speed of 15-100 cm/min is used, large linear grains are formed along the laser scan direction. Laser scan speed over 100 cm/min forms relatively smaller grains that are titled away from the scan direction. Two diode model fitting of Suns-Voc results have shown that solar cells crystallized with scan speed over 100 cm/min are limited by grain boundary recombination (n = 2). EBSD micrograph shows that the most dominant misorientation angle is 60• . Also, there were regions containing high density of twin boundaries up to ∼1.2 × 10 −8 /cm 2 . SiOx capping layer is found to be effective for reducing the required laser power density, as well as changing preferred orientation of the film from 110 to 100 in surface normal direction. Cracks are always formed during the crystallization process and found to be reducing solar cell performance significantly.

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“…The first experimental basis for these cells came from introducing impurities into Silicon to extend the sub-bandgap response of these cells and increase efficiencies [33,34]. However, this approach was expected to achieve modest efficiency improvements at best [30] and the focus switched to using quantum dots [QDs] to form the intermediate band [35,36].…”

Section: Intermediate-band Cellsmentioning

confidence: 99%

Third generation photovoltaics

Brown

2009

Laser & Photonics Reviews

169

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We review recent progress towards increasing solar cell efficiencies beyond the Shockley-Queisser efficiency limit. Four main approaches are highlighted: multi-junction cells, intermediate-band cells, hot carrier cells and spectrum conversion. Multi-junction cells use multiple solar cells that selectively absorb different regions of the solar spectrum. Intermediateband cells use one junction with multiple bandgaps to increase efficiencies. Hot-carrier cells convert the excess energy of abovebandgap photons into electrical energy. Spectrum conversion solar cells convert the incoming polychromatic sunlight into a narrower distribution of photons suited to the bandgap of the solar cell.The AM 1.5 solar spectrum along with the bandgaps of some semiconductors. Third generation photovoltaics strive to maximize the efficiency of converting polychromatic radiation into electricity.

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Extended infrared response of silicon solar cells and the impurity photovoltaic effect

Cited by 56 publications

References 19 publications

Ruling out the impact of defects on the below band gap photoconductivity of Ti supersaturated Si

Ruling out the impact of defects on the below band gap photoconductivity of Ti supersaturated Si

Diode laser crystallization processes of Si thin-film solar cells on glass

Third generation photovoltaics

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