162 research outputs found
ΠΡΡΠ΅ΡΡΠ²Π΅Π½Π½Π°Ρ ΡΠ°Π΄ΠΈΠΎΠ°ΠΊΡΠΈΠ²Π½ΠΎΡΡΡ ΠΊΠΎΠ»ΡΡΡΠ³ΠΈΠ½ΡΠΊΠΎΠΉ ΡΠ΅ΡΠΈΠΈ ΠΎΡΠ»ΠΎΠΆΠ΅Π½ΠΈΠΉ ΠΠ΅Π½ΠΈΠ½ΡΠΊΠΎΠ³ΠΎ Π³Π΅ΠΎΠ»ΠΎΠ³ΠΎ-ΡΠΊΠΎΠ½ΠΎΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠ°ΠΉΠΎΠ½Π° ΠΡΠ·Π±Π°ΡΡΠ°
Π Π°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°ΡΡΡΡ Π½Π° ΠΎΡΠ½ΠΎΠ²Π°Π½ΠΈΠΈ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ 1435 ΠΎΠ±ΡΠ°Π·ΡΠΎΠ² Π³ΠΎΡΠ½ΡΡ
ΠΏΠΎΡΠΎΠ΄ Π΅ΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΡΠ΅ ΡΠ°Π΄ΠΈΠΎΠ°ΠΊΡΠΈΠ²Π½ΡΠ΅ ΡΠ²ΠΎΠΉΡΡΠ²Π° ΠΌΠ΅Π»ΠΊΠΎ- ΠΈ ΠΊΡΡΠΏΠ½ΠΎΠ·Π΅ΡΠ½ΠΈΡΡΠΎΠ³ΠΎ Π°Π»Π΅Π²ΡΠΎΠ»ΠΈΡΠΎΠ² ΠΈ ΠΌΠ΅Π»ΠΊΠΎΠ·Π΅ΡΠ½ΠΈΡΡΠΎΠ³ΠΎ ΠΏΠ΅ΡΡΠ°Π½ΠΈΠΊΠ°, Π° ΡΠ°ΠΊΠΆΠ΅ ΠΊΠ°ΠΌΠ΅Π½Π½ΡΡ
ΡΠ³Π»Π΅ΠΉ. ΠΡΠΌΠ΅ΡΠ°Π΅ΡΡΡ ΡΠ°Π·Π»ΠΈΡΠΈΠ΅ ΠΏΠΎ Π΅ΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎΠΉ ΡΠ°Π΄ΠΈΠΎΠ°ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ ΠΌΠ΅ΠΆΠ΄Ρ ΠΎΡΠ½ΠΎΠ²Π½ΡΠΌΠΈ Π»ΠΈΡΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΌΠΈ ΡΠ°Π·Π½ΠΎΡΡΡΠΌΠΈ ΠΏΠΎΡΠΎΠ΄, ΡΠ»Π°Π³Π°ΡΡΠΈΡ
ΠΊΠΎΠ»ΡΡΡΠ³ΠΈΠ½ΡΠΊΡΡ ΡΠ΅ΡΠΈΡ. ΠΡΡΠ΅ΡΡΠ²Π΅Π½Π½Π°Ρ ΡΠ°Π΄ΠΈΠΎΠ°ΠΊΡΠΈΠ²Π½ΠΎΡΡΡ ΠΏΠΎΡΠΎΠ΄ Π·Π°ΠΊΠΎΠ½ΠΎΠΌΠ΅ΡΠ½ΠΎ ΡΠΌΠ΅Π½ΡΡΠ°Π΅ΡΡΡ ΠΎΡ Π°Π»Π΅Π²ΡΠΎΠ»ΠΈΡΠΎΠ² ΠΊ ΠΏΠ΅ΡΡΠ°Π½ΠΈΠΊΠ°ΠΌ ΠΈ ΠΊ ΡΠ³Π»ΡΠΌ. Π£Π³Π»ΠΈ ΠΏΠΎ Π΅ΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎΠΉ ΡΠ°Π΄ΠΈΠΎΠ°ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ ΡΠ΅Π·ΠΊΠΎ ΠΎΡΠ»ΠΈΡΠ°ΡΡΡΡ ΠΎΡ Π²ΠΌΠ΅ΡΠ°ΡΡΠΈΡ
ΠΏΠΎΡΠΎΠ΄
High Deposition Rate Aluminium Doped Zinc Oxide Films with Highly Efficient Light Trapping for Silicon Thin Film Solar Cells
Abstract Aluminium doped zinc oxide films were deposited on glass substrates at high rates by reactive mid frequency sputtering. The in-line sputter system allows oxygen influx along the middle and sides of a dual cathode system. The effect of varying the oxygen flow from the sides on the electrical and optical properties together with the surface morphology after wet chemical etching was investigated. Increasing the amount of oxygen flow from the sides improved the resistivity profile of static prints and gave highly conductive and transparent films in dynamic deposition mode. The etched films developed rough surface textures with effective light scattering which could be controlled by the oxygen balance between the middle and sides. Optimally textured films were used as front contacts in 1cm2 single junction Β΅c-Si:H solar cells yielding an initial efficiency of 8.4 %. The improvement in light trapping lead to short circuit densities higher than that of the reference solar cells
Chemical interaction at the buried silicon/zinc oxide thin-film solar cell interface as revealed by hard x-ray photoelectron spectroscopy
Hard X-ray photoelectron spectroscopy (HAXPES) is used to identify chemical
interactions (such as elemental redistribution) at the buried silicon
/aluminum-doped zinc oxide thin-film solar cell interface. Expanding our study
of the interfacial oxidation of silicon upon its solid-phase crystallization
(SPC), in which we found zinc oxide to be the source of oxygen, in this
investigation we address chemical interaction processes involving zinc and
aluminum. In particular, we observe an increase of zinc- and aluminum-related
HAXPES signals after SPC of the deposited amorphous silicon thin films.
Quantitative analysis suggests an elemental redistribution in the proximity of
the silicon/aluminum-doped zinc oxide interface β more pronounced for aluminum
than for zinc β as explanation. Based on these insights the complex chemical
interface structure is discussed
Understanding an empirically optimized contact
The electronic structure of the interface between the boron-doped oxygenated
amorphous silicon βwindow layerβ (a-SiOx:H(B)) and aluminum-doped zinc oxide
(ZnO:Al) was investigated using hard x-ray photoelectron spectroscopy and
compared to that of the boron-doped microcrystalline silicon (ΞΌc-
Si:H(B))/ZnO:Al interface. The corresponding valence band offsets have been
determined to be (β2.87βΒ±β0.27)βeV and (β3.37βΒ±β0.27)βeV, respectively. A
lower tunnel junction barrier height at the ΞΌc-Si:H(B)/ZnO:Al interface
compared to that at the a-SiOx:H(B)/ZnO:Al interface is found and linked to
the higher device performances in cells where a ΞΌc-Si:H(B) buffer between the
a-Si:H p-i-n absorber stack and the ZnO:Al contact is employed
Light scattering and trapping in different thin film photovoltaic device
Light trapping in different thin film technologies is investigated in the context of the European integrated project ATHLET since it allows for thinner devices and thus for reduction of costs for absorber material preparation as well as for advanced multi-junction solar cells. In silicon technology, rough interfaces are typically introduced by roughening of substrates, transparent conducting oxides (TCOs) and/or reflectors at the back side to scatter the light into the absorber material. Well known rough TCOs, plasma-textured poly-Si as well as rough Cu(In,Ga)Se2 (CIGS) absorbers are used as source for light scattering in microcrystalline silicon solar cells and compared regarding their surface roughness. The results prove that CIGS and poly silicon solar cells provide efficient light scattering by the surface features of the rough absorber
Fabrication of surface-patterned ZnO thin films using sol-gel methods and nanoimprint lithography
Surface-patterned ZnO thin films were fabricated by direct imprinting on ZnO
sol and subsequent annealing process. The polymer-based ZnO sols were deposited
on various substrates for the nanoimprint lithography and converted to
surface-patterned ZnO gel films during the thermal curing nanoimprint process.
Finally, crystalline ZnO films were obtained by subsequent annealing of the
patterned ZnO gel films. The optical characterization indicates that the
surface patterning of ZnO thin films can lead to an enhanced transmittance.
Large-scale ZnO thin films with different patterns can be fabricated by various
easy-made ordered templates using this combination of sol-gel and nanoimprint
lithography techniques.Comment: 17 pages, 5 figures; Published in Journal of Sol-Gel Science and
Technology, 201
Novel texturing method for sputtered zinc oxide films prepared at high deposition rate from ceramic tube targets
Sputtered and wet-chemically texture etched zinc oxide (ZnO) films on glass substrates are regularly applied as transparent front contact in silicon based thin film solar cells. In this study, chemical wet etching in diluted hydrofluoric acid (HF) and subsequently in diluted hydrochloric acid (HCl) on aluminum doped zinc oxide (ZnO:Al) films deposited by magnetron sputtering from ceramic tube targets at high discharge power (~10 kW/m target length) is investigated. Films with thickness of around 800 nm were etched in diluted HCl acid and HF acid to achieve rough surface textures. It is found that the etching of the films in both etchants leads to different surface textures. A two steps etching process, which is especially favorable for films prepared at high deposition rate, was systematically studied. By etching first in diluted hydrofluoric acid (HF) and subsequently in diluted hydrochloric acid (HCl) these films are furnished with a surface texture which is characterized by craters with typical diameter of around 500Β βΒ 1000 nm. The resulting surface structure is comparable to etched films sputtered at low deposition rate, which had been demonstrated to be able to achieve high efficiencies in silicon thin film solar cells
Chemical Etching of Zinc Oxide for Thin-Film Silicon Solar Cells
Chemical etching is widely applied to texture the surface of sputter-deposited zinc oxide for light scattering in thin-film silicon solar cells. Based on experimental findings from the literature and our own results we propose a model that explains the etching behavior of ZnO depending on the structural material properties and etching agent. All grain boundaries are prone to be etched to a certain threshold, that is defined by the deposition conditions and etching solution. Additionally, several approaches to modify the etching behavior through special preparation and etching steps are provided
Efforts to improve carrier mobility in radio frequency sputtered aluminium doped zinc oxide films
This study addresses the electrical and optical properties of radio frequency magnetron sputtered aluminum doped zinc oxide (ZnO:Al) films. The main focus was on the improvement in carrier mobility mu to achieve simultaneously high transparency for visible and particularly near-infrared light and low resistivity. The influence of Al concentration in the target, film thickness, sputter power, deposition pressure, and substrate temperature on material properties was investigated. The structural, compositional, electrical and optical properties were studied using x-ray diffraction, secondary ion mass spectrometry (SIMS), room temperature Hall effect measurements and spectral photometry, respectively. All ZnO:Al films were polycrystalline and preferentially oriented along [002]. The grain size along the direction of growth increased with higher Al doping and with increasing film thickness. The SIMS measurements revealed that the Al concentration in the film was nearly the same as in the target. Carrier concentration N and mobility mu are determined by the target Al concentration. In addition mu is influenced by the film thickness and the sputter pressure. For each Al concentration, the highest mu was generally observed at low deposition pressures. By using a target with low Al2O3 concentration of 0.5 wt %, mu could be improved up to 44.2 cm(2)/V s while maintaining the electrical resistivity rho as low as 3.8x10(-4) Omega cm. For these films the transparency in the near-infrared wavelength range strongly improved which makes them particularly interesting for the application in optoelectronic devices like thin-film solar cells. The mu-N dependence for films deposited under diverse conditions was studied to identify a practical limit for mu. (C) 2004 American Institute of Physics
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