The utilization of microcrystalline Si and SiC for the efficiency improvement in a-Si solar cells

Ma, Wen; Saida, Takahiro; Lim, C.C.; Aoyama, Shota; Okamoto, H.; Hamakawa, Yoshihiro

doi:10.1109/wcpec.1994.519987

Cited by 7 publications

(14 citation statements)

References 4 publications

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“…Indeed, the μc-Si:H P-layer has a lower surface band bending (sbb) and lower activation energy than P-a-SiC:H. These properties help to improve the builtin potential (V bi ), open-circuit voltage (V oc ) and fill factor (FF) of solar cells employing such a double window layer structure relative to a standard cell having a single P-a-SiC:H window layer [13]. These modelling results have received confirmation from the experimental work of Ma et al [14]. The problem with a single P-μc-Si:H window is the large valence band discontinuity, since it has been shown by the IPE measurements of Xu et al [15] that the P-μc-Si:H/a-Si:H band discontinuity is almost totally on the valence band side.…”

Section: Introductionmentioning

confidence: 76%

“…'sbb' is the TCO/P surface band bending, which we have taken to be ∼0.16 eV, the measured value [14] for this quantity for P-μc-Si:H, employed in all double window structures. A value of 0.2 eV has been assumed for P-μc-SiO x :H, in simulations involving such a single P-layer.…”

Section: Simulation Modelmentioning

confidence: 99%

“…In the latter case, in the absence of any measured data (to our knowledge), we have apportioned half the band discontinuity to the valence band and this fact hinders hole collection and brings down the FF. Also the sbb is 0.16 eV for TCO/P-μc-Si:H [14]. As there are no experimental data for the TCO/P-μc-SiO x :H band bending, we have taken the value of 0.2 eV (sixth row of Tab.…”

Section: The Window and Emitter Designmentioning

confidence: 99%

“…P-doped μc-SiO x :H is also a promising P-layer, since it is more transparent (having a wider band gap) than P-a-SiC:H and its doping density can be adjusted to yield high conductivity. We have in this study therefore also tried out by modelling a P-μc-Si:H/P-μc-SiO x :H double window structure, primarily because we know the TCO/P sbb for the case of P-μc-Si:H [14], but it is unknown in the case of P-μc-SiO x :H. Nevertheless we have also experimented with a single P-μc-SiO x :H window layer, assuming a range of values for the ZnO:Al/P-μc-SiO x :H sbb. In all cases an ultra-thin intrinsic buffer layer follows the window P layers, both to prevent boron tailing into the intrinsic layer and to obtain a less defective P/I interface.…”

Section: Introductionmentioning

confidence: 99%

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Towards 12% stabilised efficiency in single junction polymorphous silicon solar cells: experimental developments and model predictions

2016

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We have combined recent experimental developments in our laboratory with modelling to devise ways of maximising the stabilised efficiency of hydrogenated amorphous silicon (a-Si:H) PIN solar cells. The cells were fabricated using the conventional plasma enhanced chemical vapour deposition (PECVD) technique at various temperatures, pressures and gas flow ratios. A detailed electrical-optical simulator was used to examine the effect of using wide band gap P-and N-doped μc-SiOx:H layers, as well as a MgF2 anti-reflection coating (ARC) on cell performance. We find that with the best quality a-Si:H so far produced in our laboratory and optimised deposition parameters for the corresponding solar cell, we could not attain a 10% stabilised efficiency due to the high stabilised defect density of a-Si:H, although this landmark has been achieved in some laboratories. On the other hand, a close cousin of a-Si:H, hydrogenated polymorphous silicon (pm-Si:H), a nano-structured silicon thin film produced by PECVD under conditions close to powder formation, has been developed in our laboratory. This material has been shown to have a lower initial and stabilised defect density as well as higher hole mobility than a-Si:H. Modelling indicates that it is possible to attain stabilised efficiencies of 12% when pm-Si:H is incorporated in a solar cell, deposited in a NIP configuration to reduce the P/I interface defects and combined with P-and N-doped μc-SiOx:H layers and a MgF2 ARC.

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Section: Introductionmentioning

confidence: 76%

Section: Simulation Modelmentioning

confidence: 99%

Section: The Window and Emitter Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Towards 12% stabilised efficiency in single junction polymorphous silicon solar cells: experimental developments and model predictions

2016

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“…[1][2][3][4] In using such films as a p layer, ineffective absorption loss in the p layer cannot be ignored because the optical band gap of those films is limited to less than about 2.6 eV due to the increase in electrical resistivity with the increase of optical band gap. Thus, new p-type materials with higher optical transparency than these materials should be developed to convert the solar spectrum into electrical energy as much as possible.…”

mentioning

confidence: 99%

Boron-doped amorphous diamondlike carbon as a new p-type window material in amorphous silicon p-i-n solar cells

Lee

Lim

1998

Applied Physics Letters

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A boron-doped hydrogenated amorphous diamondlike carbon (a-DLC:H͒ was prepared using a mercury-sensitized photochemical vapor deposition ͑photo-CVD͒ method. The source gases were B 2 H 6 and C 2 H 4 . By increasing the boron doping ratio (B 2 H 6 /C 2 H 4 ) from 0 to 12 000 ppm, the dark conductivity increased from ϳ10 Ϫ9 to ϳ10 Ϫ7 S/cm. A boron-doped a-DLC:H with an energy band gap of 3.8 eV and a dark conductivity of 1.3ϫ10 Ϫ8 S/cm was obtained at a doping ratio of 3600 ppm. By using this film, amorphous silicon (a-Si͒ solar cells with a novel p-a-DLC:H/p-a-SiC double p-layer structure were fabricated using the photo-CVD method and the cell photovoltaic characteristics were investigated as a function of a-DLC:H layer thickness. The open circuit voltage increased from 0.766 V for the conventional cell with a 40-Å-thick p-a-SiC to 0.865 V for the cell with a p-a-DLC:H ͑15 Å͒/p-a-SiC ͑40 Å͒ double p-layer structure. The thin ͑Ͻ15 Å͒ p-a-DLC:H layer proved to be an excellent hole emitter as a wide band gap window layer.

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Design and Simulation of GaAs/InP and Si/SiC Heterojunction Solar Cells

Garg¹,

Ratnesh²

2023

Lecture Notes in Electrical Engineering

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The utilization of microcrystalline Si and SiC for the efficiency improvement in a-Si solar cells

Cited by 7 publications

References 4 publications

Towards 12% stabilised efficiency in single junction polymorphous silicon solar cells: experimental developments and model predictions

Towards 12% stabilised efficiency in single junction polymorphous silicon solar cells: experimental developments and model predictions

Boron-doped amorphous diamondlike carbon as a new p-type window material in amorphous silicon p-i-n solar cells

Design and Simulation of GaAs/InP and Si/SiC Heterojunction Solar Cells

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