EP1807873A1 - Photovoltaic cell - Google Patents

Photovoltaic cell

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Publication number
EP1807873A1
EP1807873A1 EP05798617A EP05798617A EP1807873A1 EP 1807873 A1 EP1807873 A1 EP 1807873A1 EP 05798617 A EP05798617 A EP 05798617A EP 05798617 A EP05798617 A EP 05798617A EP 1807873 A1 EP1807873 A1 EP 1807873A1
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EP
European Patent Office
Prior art keywords
layer
semiconductor material
doped semiconductor
photovoltaic cell
substrate
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EP05798617A
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German (de)
French (fr)
Inventor
Hans-Josef Sterzel
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BASF SE
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BASF SE
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/0256—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by the material
    • H01L31/0264—Inorganic materials
    • H01L31/032—Inorganic materials including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312
    • H01L31/0321—Inorganic materials including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312 characterised by the doping material
    • H—ELECTRICITY
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    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/0256—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by the material
    • H01L31/0264—Inorganic materials
    • H01L31/0296—Inorganic materials including, apart from doping material or other impurities, only AIIBVI compounds, e.g. CdS, ZnS, HgCdTe
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    • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/0256—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by the material
    • H01L31/0264—Inorganic materials
    • H01L31/032—Inorganic materials including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312
    • H—ELECTRICITY
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    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/036—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes
    • H01L31/0392—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate
    • H—ELECTRICITY
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    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/036—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes
    • H01L31/0392—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate
    • H01L31/03925—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate including AIIBVI compound materials, e.g. CdTe, CdS
    • H—ELECTRICITY
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    • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/036—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes
    • H01L31/0392—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate
    • H01L31/03926—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate comprising a flexible substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/06—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers
    • H01L31/068—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/547—Monocrystalline silicon PV cells

Definitions

  • the invention relates to photovoltaic cells and the photovoltaically active semiconductor material contained therein.
  • Photovoltaically active materials are semiconductors that convert light into electrical energy.
  • the basics have been known for a long time and are used technically. Almost most of the technically used solar cells are based on crystalline silicon (monocrystalline or polycrystalline). In a boundary layer between p- and n-type silicon, incident photons excite electrons of the semiconductor, so that they are lifted from the valence band into the conduction band.
  • the height of the energy gap between the valence band and the conduction band limits the maximum possible efficiency of the solar cell. For silicon, this is about 30% when exposed to sunlight. In practice, on the other hand, an efficiency of about 15% is achieved because some of the charge carriers are re-combined by different processes or deactivated by further mechanisms and thus removed from use.
  • silicon With an energy gap around 1, 1 eV, silicon has a fairly good value for use. By reducing the energy gap, more charge carriers are transported into the conduction band, but the cell voltage becomes lower. Correspondingly, higher cell voltages are achieved with larger energy gaps, but since fewer photons are present for excitation, lower usable currents are available.
  • tandem cells Many arrangements, such as the series arrangement of semiconductors with different energy gaps, in so-called tandem cells have been proposed in order to achieve higher efficiencies. Due to their complex structure, however, these are hardly economically feasible.
  • a new concept is to generate an intermediate level within the energy gap (up-conversion). This concept is described, for example, in the Proceedings of the 14th Workshop on Quantum Solar Energy Conversion Quantasol 2002, March, 17-23, 2002, Rauris, Salzburg, Austria, "Improving Solar Cells Efficiencies by the Up-Conversion", T. Trupke, MA Green, P. Cube or "Increasing the Efficiency of Ideal Solar Cells by Photon Induced Tranisitions at intermediate levels ", A. Luque and A. Marti, Phys. Rev. Letters, Vol. 78, No. 26, June 1997, 5014-5017. For a band gap of 1.995 eV and an energy of the intermediate level at 0.713 eV, a maximum efficiency of 63.17% is calculated.
  • the desired intermediate energy level in the bandgap is increased by replacing part of the telluran ions in the anion lattice with the substantially more electronegative oxygen ion.
  • Tellurium was replaced by ion implantation in thin films by oxygen.
  • a major disadvantage of this class of substances is that the solubility of the oxygen in the semiconductor is extremely low. It follows that, for example, the compounds Zn Vx Mn x Te Vy O y with y greater than 0.001 are not thermodynamically stable. Upon irradiation for a long time, they will lapse into the stable tellurides and oxides. Use of up to 10 at% tellurium by oxygen would be desirable, but such compounds are not stable.
  • Zinc telluride which has a direct band gap of 2.32 eV at room temperature, would be an ideal semiconductor for the intermediate level technology because of this large band gap.
  • Zinc can be replaced by manganese continuously in zinc telluride, whereby the band gap increases to about 2.8 eV with MnTe ("Optical Properties of epitaxial Zn Mn Te and ZnMgTe films for a wide range of alloy compostions", X. Liu et al., J. Appl. Phys., Vol. 91, No. 5, March 2002, 2859-2865; "Bandgap of Znv x Mn x Te: non linear dependence on compostion and temperature", HC Mertins et al., Semicond. Sci. Technol. 8 (1993) 1634-1638).
  • Zn 1 ⁇ Mn x Te can be p-type doped with up to 0.2 mol% phosphorus, with an electrical conductivity between 10 and 30 ⁇ '1 cm ' 1 is achieved ("Electrical and Magnetic Properties of Phosphorus Doped BuIk Znv x Mn x Te ", Le Van Khoi et al., Moudavian Journal of Physical Sciences, No. 1, 2002, 11-14.)
  • n-type species are obtained (" aluminum-doped n-type ZnTe layers grown by molecular beam epitaxy ", JH Chang et al., Appl. Phys. Letters, VoI 79, No.
  • the object of the present invention is to provide a photovoltaic cell with a high efficiency and a high electric power, which avoids the disadvantages of the prior art. Furthermore, it is the object of the present invention in particular to provide a photovoltaic cell with a thermodynamically stable photovoltaically active semiconductor material, wherein the semiconductor material contains an intermediate level in the energy gap.
  • a photovoltaic cell with a photovoltaically active semiconductor material characterized in that the photovoltaically active semiconductor material is a p- or an n-doped semiconductor material with mixed compounds of the formula (I):
  • x number from 0.01 to 0.99
  • y number from 0.001 to 0.2
  • a number from 1 to 2
  • b number from 1 to 3.
  • the task is surprisingly solved completely different than the literature mentioned could be expected.
  • the tellurium is not replaced by a much more electronegative element, but rather silicon is introduced into the semiconductor material with the formula Zn 1-11 Mn x Te. This is surprising insofar as the electronegativity of silicon differs only slightly from that of 2.1 with tellurium 2.1.
  • the variable x can assume values of 0.01 to 0.99
  • y can assume values of 0.001 to 0.2, preferably of 0.005 to 0.1.
  • the variable a can take values from 1 to 2
  • b can take values from 1 to 3.
  • the photovoltaic cell according to the invention has the advantage that the photovoltaically active semiconductor material used is thermodynamically stable even after introduction of silicon telluride. Furthermore, the photovoltaic cell according to the invention has a high degree of efficiency (up to 60%) since the silicon telluride Si a Te b generates intermediate levels in the energy gap of the photovoltaically active semiconductor material. Without intermediate level, only such photons can be electrons or Lift charge carriers from the valence band into the conduction band, which have at least the energy gap energy. Photons of higher energy also contribute to the efficiency, the excess of energy with respect to the band gap being lost as heat. With an intermediate level present in the semiconductor material used for the present invention, which can be partially occupied, more photons can contribute to the excitation.
  • the photovoltaic cell of the present invention is constructed to include a p-doped and an n-doped semiconductor material, these two semiconductor materials adjoining each other to form a p-n junction.
  • both the p- and the n-doped semiconductor material largely consists of mixed compounds of the formula (I), wherein the material is further doped with donor ions in the p-doped Halbleiterma ⁇ material and acceptor ions in the n-doped semiconductor material.
  • the p-doped semiconductor material contains at least one element from the group As and P with an atomic concentration of up to 0.1 at% and the n-doped semiconductor material at least one element from the group AI, In and Ga with an atomic concentration of up to to 0.5 at%.
  • Preferred dopants are aluminum and phosphorus.
  • this comprises a substrate, in particular an electrically conductive substrate, a p-layer of the p-doped semiconductor material having a thickness of 0.1 to 10 .mu.m, preferably 0.3 to 3 .mu.m, and an n Layer of the n-doped semiconductor material having a thickness of 0.1 to 10 .mu.m, preferably 0.3 to 3 microns.
  • the substrate is a flexible metal foil or a flexible metal sheet.
  • inflexible substrates such as glass or silicon
  • wind forces have to be absorbed by complex supporting constructions in order to avoid breakage of the solar module.
  • twisting is possible by means of flexibility, it is possible to use very simple and inexpensive supporting structures which do not have to be torsionally stiff.
  • a stainless steel sheet is particularly used in the present invention.
  • the invention further relates to a method for producing a photovoltaic cell according to the invention, comprising coating a substrate with at least one respective layer of the p-doped semiconductor material and a layer of the n-doped semiconductor material, the layers having a thickness of 0 , 1 to 10 microns, preferably from 0.3 to 3 microns.
  • the coating of the substrate with the p or n layer preferably comprises at least one deposition method selected from the group sputtering, laser ablation, electrochemical deposition or electroless deposition.
  • the already p- or n-doped semiconductor material with mixed compounds of the formula (I) can be applied to the substrate as a layer.
  • a layer of the semiconductor material may be first generated without p- or n-doping by the deposition process and this layer then p- or n-doped.
  • the introduction of silicon in the form of silicon telluride according to the invention is (if the respective layer produced by one of the abovementioned deposition methods has not yet been formed accordingly) preferably carried out subsequent to the performance of the deposition process (and optionally to the p- or n-doping).
  • Sputtering refers to the ejection of atoms from a sputtering target serving as an electrode by accelerated ions and the deposition of the ejected material on a substrate (eg stainless steel).
  • a substrate eg stainless steel
  • sputtering targets containing zinc, manganese, tellurium and silicon are produced by fusing together the constituents or individual constituents of the semiconductor material are sputtered onto the substrate one after the other and then to a temperature of 400 to 900 0 C heated.
  • zinc, manganese, tellurium and silicon in a purity of at least 99.5% are used to produce the sputtering target.
  • Zinc, manganese, tellurium and silicon telluride (Si a Te b ) are fused in a dehydrated quartz tube under vacuum at temperatures of 1200 to 1400 0 C, for example.
  • doping elements for a p-type or n-type doping are preferably introduced into the sputtering target.
  • the doping elements preferably aluminum for n-conduction and phosphorus for p-conduction, are accordingly added to the sputtering target from the outset.
  • the compounds AITe or Zn 3 P 2 are so temperature stable that they survive the sputtering process without significant change in stoichiometry.
  • a layer with a doping is then sputtered onto the substrate and immediately thereafter a further layer with the opposite doping.
  • Another preferred deposition method according to the invention is the electrochemical deposition of Zn 1 Mn x Te on the electrically conductive substrate.
  • the electrochemical deposition of ZnTe is described in "Thin Films of ZnTe Electrodeposited on Stainless Steel", AE Rakhsan and Pradup, Appl. Phys. A (2003), Pub., Online, Dec. 19, 2003, Springer-Verlag; "Electrodeposition of ZnTe for photovoltaic alls", B. Bozzini et al., Thin Solid Films, 361-362, (2000) 288-295; "Electrochemical Deposition of ZnTe Thins films ", T.
  • the substrate contains an aqueous solution containing Zn 2+, Mn 2+ and TeO 3 2 ions, at temperatures of 30 to 90 0 C is crosslinked with hypophosphorous acid (H 3 PO 2 ) as a reducing agent.
  • hypophosphorous acid H 3 PO 2
  • the hypophosphorous acid reduces TeO 3 2 " to Te 2" . This also depositions on electrically non-conductive substrates are possible.
  • the method according to the invention comprises the following method steps:
  • the electrically conductive substrate is coated, for example by sputtering, electrochemical deposition or electroless deposition, with a first layer of Zn 1 Mn x Te.
  • the substrate is preferably a metal sheet or a metal foil.
  • silicon is introduced into this first layer in step b) to produce mixed compounds of the formula (I).
  • the introduction of silicon takes place, for example, by applying Si 2 Te 3 to the first layer by sputtering and then by a thermal post-treatment at 600 to 1200 0 C, preferably 800 to 1000 0 C, a mixed crystallization and thus the desired composition er ⁇ is sufficient.
  • a p- or n-doping is then generated by doping with donor atoms or acceptor atoms.
  • the first layer is doped either with phosphorus (for example from PCI 3 ) to the p-type conductor or with aluminum (for example from AICI 3 ) to the n-type conductor.
  • step d) the second layer of Zn 1 -x Mn x Te is then deposited on the first layer. This can be done, for example, the same deposition method as in step a).
  • step e silicon is introduced into the second layer as described with reference to the first layer for step b).
  • step f) The doping generated in step f) is opposed to the doping generated in step c), so that one layer has a p-type doping and the other layer has an n-type doping.
  • an electrically conductive transparent layer and a protective layer are applied to the second layer.
  • the electrically conductive transparent layer may be, for example, a layer of indium tin oxide or aluminum zinc oxide. It also preferably carries printed conductors for the electrical contacting of the photovoltaic cell according to the invention.
  • the protective layer can be, for example, a layer of SiO x , which is preferably applied by CVD or PVD.
  • a layer of a material may serve as a protective layer which is produced in the prior art for aroma-tight films (eg coffee packaging).
  • Si 2 Te 3 were weighed into a quartz tube with an inner diameter of 11 mm and a length of about 15 cm.
  • the Si 2 Te 3 wur ⁇ de previously separately prepared by adding silicon and tellurium were taken at 1,000 0 C in an evacua- wholesome quartz tube to react.
  • the tube was heated under vacuum to 300 ° C. for 10 minutes to drain and then under a pressure lower than 0.1 mbar melted off.
  • the tube was heated in an oven at 300 ° C / h to 1300 0 C, the temperature for 10 h at 1300 0 C left and then allowed to cool the oven.
  • the furnace was tilted about a drive 30 times per hour about its longitudinal axis to see through the melt in the quartz tube.
  • this material is sputtered onto a substrate.
  • electrolyses were carried out in a 500 ml flat-bottomed reaction vessel with double jacket, internal thermometer and bottom outlet valve.
  • the cathode used was a stainless steel sheet (100 ⁇ 70 ⁇ 0.5).
  • the anode consisted of MKUSF04 (graphite).
  • the deposition was carried out at a cathode area of -50 cm 2 ( ⁇ 2 mA / cm z ). After completion of the electrolysis, the cathode was removed, rinsed with distilled water and dried. The weight gain is 26.9 mg. The deposit has a deep dark brown color.

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  • Engineering & Computer Science (AREA)
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Abstract

The invention relates to a photovoltaic cell comprising a photovoltaically active semiconductor material. Said photovoltaically active semiconductor material is a p- or n-doped semiconductor material with mixed compounds of formula (I): (Zn1-xMnxTe)1-y(SiaTeb)y, in which x = a number from 0.01 to 0.99, y = a number from 0.01 to 0.2, a = a number from 1 to 2 and b = a number from 1 to 3.

Description

Photovoltaische ZellePhotovoltaic cell
Beschreibungdescription
Die Erfindung betrifft photovoltaische Zellen und das darin enthaltene photovoltaisch aktive Halbleitermaterial.The invention relates to photovoltaic cells and the photovoltaically active semiconductor material contained therein.
Photovoltaisch aktive Materialien sind Halbleiter, welche Licht in elektrische Energie umsetzen. Die Grundlagen hierzu sind lange bekannt und werden technisch genutzt. Nahezu die meisten der technisch genutzten Solarzellen basieren auf kristallinem Sili¬ zium (ein- oder polykristallin). In einer Grenzschicht zwischen p- und n-leitendem Silizi¬ um regen einfallende Photonen Elektronen des Halbleiters an, so dass sie vom Va- lenzband in das Leitungsband gehoben werden.Photovoltaically active materials are semiconductors that convert light into electrical energy. The basics have been known for a long time and are used technically. Almost most of the technically used solar cells are based on crystalline silicon (monocrystalline or polycrystalline). In a boundary layer between p- and n-type silicon, incident photons excite electrons of the semiconductor, so that they are lifted from the valence band into the conduction band.
Die Höhe der Energielücke zwischen dem Valenzband und dem Leitungsband limitiert den maximal möglichen Wirkungsgrad der Solarzelle. Beim Silizium ist dies circa 30% bei Bestrahlung mit Sonnenlicht. In der Praxis erreicht man dagegen einen Wirkungs- grad von circa 15%, weil ein Teil der Ladungsträger durch verschiedene Prozesse re¬ kombiniert oder durch weitere Mechanismen deaktiviert und so der Nutzung entzogen wird.The height of the energy gap between the valence band and the conduction band limits the maximum possible efficiency of the solar cell. For silicon, this is about 30% when exposed to sunlight. In practice, on the other hand, an efficiency of about 15% is achieved because some of the charge carriers are re-combined by different processes or deactivated by further mechanisms and thus removed from use.
Aus DE 102 23 744 A1 sind alternative photovoltaisch aktive Materialien und diese enthaltende Photovoltaikzellen bekannt, die den Wirkungsgrad herabsetzende Ver¬ lustmechanismen in einem verringerten Maße aufweisen.From DE 102 23 744 A1, alternative photovoltaically active materials and photovoltaic cells containing them are known, which have loss mechanisms which reduce the efficiency to a reduced extent.
Mit einer Energielücke um 1 ,1 eV weist Silizium einen für die Nutzung recht guten Wert auf. Durch ein Verkleinern der Energielücke werden zwar mehr Ladungsträger ins Lei- tungsband befördert, die Zellspannung wird jedoch niedriger. Entsprechend werden bei größeren Energielücken zwar höhere Zellspannungen erreicht, da aber weniger Photo¬ nen zur Anregung vorhanden sind, stehen niedrigere nutzbare Ströme zur Verfügung.With an energy gap around 1, 1 eV, silicon has a fairly good value for use. By reducing the energy gap, more charge carriers are transported into the conduction band, but the cell voltage becomes lower. Correspondingly, higher cell voltages are achieved with larger energy gaps, but since fewer photons are present for excitation, lower usable currents are available.
Viele Anordnungen wie die Serienanordnung von Halbleitern mit verschiedenen Ener- gielücken, in sogenannten Tandemzellen wurden vorgeschlagen, um höhere Wir¬ kungsgrade zu erreichen. Diese sind wegen ihres komplexen Aufbaus jedoch wirt¬ schaftlich kaum zu realisieren.Many arrangements, such as the series arrangement of semiconductors with different energy gaps, in so-called tandem cells have been proposed in order to achieve higher efficiencies. Due to their complex structure, however, these are hardly economically feasible.
Ein neues Konzept besteht darin, innerhalb der Energielücke ein Zwischenniveau zu generieren (Up-Conversion). Dieses Konzept ist beispielsweise beschrieben in Pro- ceedings of the 14th Workshop on Quantum Solar Energy Conversion-Quantasol 2002, March, 17-23, 2002, Rauris, Salzburg, Österreich, "Improving solar cells efficiencies by the up-conversion", Tl. Trupke, M.A. Green, P. Würfel oder "Increasing the Efficiency of Ideal Solar Cells by Photon Induced Tranisitions at intermediate Levels", A. Luque and A. Marti, Phys. Rev. Letters, Vol. 78, Nr. 26, June 1997, 5014-5017. Für eine Bandlü- cke von 1 ,995 eV und eine Energie des Zwischenniveaus bei 0,713 eV ergibt sich rechnerisch ein maximaler Wirkungsgrad von 63,17%.A new concept is to generate an intermediate level within the energy gap (up-conversion). This concept is described, for example, in the Proceedings of the 14th Workshop on Quantum Solar Energy Conversion Quantasol 2002, March, 17-23, 2002, Rauris, Salzburg, Austria, "Improving Solar Cells Efficiencies by the Up-Conversion", T. Trupke, MA Green, P. Cube or "Increasing the Efficiency of Ideal Solar Cells by Photon Induced Tranisitions at intermediate levels ", A. Luque and A. Marti, Phys. Rev. Letters, Vol. 78, No. 26, June 1997, 5014-5017. For a band gap of 1.995 eV and an energy of the intermediate level at 0.713 eV, a maximum efficiency of 63.17% is calculated.
Spektroskopisch wurden derartige Zwischenniveaus beispielsweise am System CdVyM^OxTe1-X oder an Zn1-XMnxOyTeVy nachgewiesen. Dies ist beschrieben in "Band anticrossing in group H-OxVI1-X highly mismatched alloys: CdvyMnyOχTevχ quaternaries synthesized by O ion Implantation", W. Walukiewicz et al., Appl. Phys. Letters, VoI 80, Nr. 9, March 2002, 1571-1573 und in "Synthesis and optical properties of H-O-Vl highly mismatched alloys", W. Walukiewicz et al., J. Appl. Phys. Vol. 95, Nr. 11 , June 2004, 6232-6238. Demnach wird das erwünschte energetische Zwischenniveau in der Band- lücke dadurch erhöht, dass im Anionengitter ein Teil der Telluranionen durch das we¬ sentlich elektronegativere Sauerstoffion ersetzt wird. Dabei wurde Tellur durch Ionen¬ implantation in dünnen Filmen durch Sauerstoff ersetzt. Ein wesentlicher Nachteil die¬ ser Stoffklasse besteht darin, dass die Löslichkeit des Sauerstoffs im Halbleiter äußerst gering ist. Daraus folgt, dass beispielsweise die Verbindungen ZnVxMnxTeVyOy mit y größer als 0,001 thermodynamisch nicht stabil sind. Bei Bestrahlung über längere Zeit verfallen sie in die stabilen Telluride und Oxide. Ein Einsatz von bis zu 10 At-% Tellur durch Sauerstoff wäre erwünscht, wobei solche Verbindungen jedoch nicht stabil sind.Spectroscopy such intermediate levels were, for example, the system Cd Vy M ^ O x Te 1 - detected X Mn x O y Te y V - X or Zn. 1 This is described in "Band anticrossing in group HO x VI 1 - X highly mismatched alloys: CdvyMn y OχTevχ quaternaries synthesized by ion implantation", W. Walukiewicz et al., Appl. Phys. Letters, Vol. 80, No. 9, March 2002, 1571-1573 and in "Synthesis and optical properties of HO-VL highly mismatched alloys", W. Walukiewicz et al., J. Appl. Phys. Vol. 95, No. 11, June 2004, 6232-6238. Accordingly, the desired intermediate energy level in the bandgap is increased by replacing part of the telluran ions in the anion lattice with the substantially more electronegative oxygen ion. Tellurium was replaced by ion implantation in thin films by oxygen. A major disadvantage of this class of substances is that the solubility of the oxygen in the semiconductor is extremely low. It follows that, for example, the compounds Zn Vx Mn x Te Vy O y with y greater than 0.001 are not thermodynamically stable. Upon irradiation for a long time, they will lapse into the stable tellurides and oxides. Use of up to 10 at% tellurium by oxygen would be desirable, but such compounds are not stable.
Zinktellurid, das bei Raumtemperatur eine direkte Bandlücke von 2,32 eV aufweist, wäre wegen dieser großen Bandlücke ein idealer Halbleiter für die Zwischenniveau- technologie. Zink lässt sich gut in Zinktellurid kontinuierlich durch Mangan substituie¬ ren, wobei die Bandlücke auf circa 2,8 eV bei MnTe anwächst („Optical Properties of epitaxial Zn Mn Te and ZnMgTe films for a wide ränge of alloy compostions", X. Liu et al., J. Appl. Phys. Vol. 91 , Nr. 5, March 2002, 2859-2865; „Bandgap of ZnvxMnxTe: non linear dependence on compostion and temperature", H. C. Mertins et al., Semicond. Sei. Technol. 8 (1993) 1634-1638).Zinc telluride, which has a direct band gap of 2.32 eV at room temperature, would be an ideal semiconductor for the intermediate level technology because of this large band gap. Zinc can be replaced by manganese continuously in zinc telluride, whereby the band gap increases to about 2.8 eV with MnTe ("Optical Properties of epitaxial Zn Mn Te and ZnMgTe films for a wide range of alloy compostions", X. Liu et al., J. Appl. Phys., Vol. 91, No. 5, March 2002, 2859-2865; "Bandgap of Znv x Mn x Te: non linear dependence on compostion and temperature", HC Mertins et al., Semicond. Sci. Technol. 8 (1993) 1634-1638).
Zn1^MnxTe lässt sich mit bis zu 0,2 Mol-% Phosphor p-leitend dotieren, wobei eine elektrische Leitfähigkeit zwischen 10 und 30 Ω'1cm'1 erreicht wird („Electrical and Magnetic Properties of Phosphorus Doped BuIk ZnvxMnxTe", Le Van Khoi et al., MoI- davian Journal of Physical Sciences, Nr. 1 , 2002, 11-14). Durch partielles Ersetzen von Zink durch Aluminium werden n-leitende Spezies erhalten („Aluminium-doped n-type ZnTe layers grown by molecular-beam epitaxy", J. H. Chang et al., Appl. Phys. Letters, VoI 79, Nr. 6, august 2001 , 785-787; "Aluminium doping of ZnTe grown by MOPVE", S.l. Gheyas et al., Appl. Surface Science 100/101 (1996) 634-638; "Electrical Transport and Photoelectronic Properties of ZnTe: AI Crystals", T.L. Lavsen et al., J. Appl. Phys., VoI 43, Nr. 1 , Jan 1972, 172-182). Mit Dotierungsgraden um 4*1018 AI/cm3 können e- lektrische Leitfähigkeiten um 50 bis 60 Ω"1cm"1 erreicht werden.Zn 1 ^ Mn x Te can be p-type doped with up to 0.2 mol% phosphorus, with an electrical conductivity between 10 and 30 Ω '1 cm ' 1 is achieved ("Electrical and Magnetic Properties of Phosphorus Doped BuIk Znv x Mn x Te ", Le Van Khoi et al., Moudavian Journal of Physical Sciences, No. 1, 2002, 11-14.) By partially replacing zinc with aluminum, n-type species are obtained (" aluminum-doped n-type ZnTe layers grown by molecular beam epitaxy ", JH Chang et al., Appl. Phys. Letters, VoI 79, No. 6, August 2001, 785-787;" Aluminum Doping of ZnTe grown by MOPVE ", Sl Gheyas et al., Appl. Surface Science 100/101 (1996) 634-638; "Electrical Transport and Photoelectronic Properties of ZnTe: Al Crystals", TL Lavsen et al., J. Appl. Phys. VoI 43, No. 1, Jan 1972, 172-182). With doping degrees around 4 * 10 18 Al / cm 3 e- lektrische conductivities by 50 to 60 Ω "1 cm " 1 can be achieved.
Die Aufgabe der vorliegenden Erfindung besteht darin, eine photovoltaische Zelle mit einem hohen Wirkungsgrad und einer hohen elektrischen Leistung bereitzustellen, die die Nachteile des Standes der Technik vermeidet. Weiterhin ist es Aufgabe der vorlie¬ genden Erfindung insbesondere eine photovoltaische Zelle mit einem thermodyna- misch stabilen photovoltaisch aktiven Halbleitermaterial bereitzustellen, wobei das Halbleitermaterial ein Zwischenniveau in der Energielücke enthält.The object of the present invention is to provide a photovoltaic cell with a high efficiency and a high electric power, which avoids the disadvantages of the prior art. Furthermore, it is the object of the present invention in particular to provide a photovoltaic cell with a thermodynamically stable photovoltaically active semiconductor material, wherein the semiconductor material contains an intermediate level in the energy gap.
Diese Aufgabe wird erfindungsgemäß gelöst durch eine photovoltaische Zelle mit ei¬ nem photovoltaisch aktiven Halbleitermaterial, dadurch gekennzeichnet, dass das pho¬ tovoltaisch aktive Halbleitermaterial ein p- oder ein n-dotiertes Halbleitermaterial mit Mischverbindungen der Formel (I) ist:This object is achieved according to the invention by a photovoltaic cell with a photovoltaically active semiconductor material, characterized in that the photovoltaically active semiconductor material is a p- or an n-doped semiconductor material with mixed compounds of the formula (I):
(Zn1.xMnxTe)i.y(SiaTeb)y (I)(Zn 1 x Mn x Te) i. y (Si a Te b ) y (I)
mit x = Zahl von 0,01 bis 0,99, y = Zahl von 0,001 bis 0,2, a = Zahl von 1 bis 2 und b = Zahl von 1 bis 3.where x = number from 0.01 to 0.99, y = number from 0.001 to 0.2, a = number from 1 to 2 and b = number from 1 to 3.
Damit wird die Aufgabe überraschenderweise völlig anders gelöst als es die genannten Literaturstellen erwarten ließen. Zur Erzeugung von Zwischenniveaus in der Energielü¬ cke wird das Tellur nicht durch ein wesentlich elektronegativeres Element ersetzt, son¬ dern es wird Silizium in das Halbleitermaterial mit der Formel Zn1-11MnxTe eingebracht. Dies ist insofern überraschend, als sich die Elektronegativität von Silizium mit 1 ,9 nur geringfügig von der des Tellurs mit 2,1 unterscheidet.Thus, the task is surprisingly solved completely different than the literature mentioned could be expected. To generate intermediate levels in the energy gap, the tellurium is not replaced by a much more electronegative element, but rather silicon is introduced into the semiconductor material with the formula Zn 1-11 Mn x Te. This is surprising insofar as the electronegativity of silicon differs only slightly from that of 2.1 with tellurium 2.1.
Die Variable x kann Werte von 0,01 bis 0,99 annehmen, y kann Werte von 0,001 bis 0,2, vorzugsweise von 0,005 bis 0,1 annehmen. Die Variable a kann Werte von 1 bis 2 annehmen, b kann Werte von 1 bis 3 annehmen. Bevorzugt sind a = 2 und b = 3, was als Stöchiometrie Si2Te3 ergibt.The variable x can assume values of 0.01 to 0.99, y can assume values of 0.001 to 0.2, preferably of 0.005 to 0.1. The variable a can take values from 1 to 2, b can take values from 1 to 3. Preferably a = 2 and b = 3, which gives Si 2 Te 3 as stoichiometry.
Die erfindungsgemäße photovoltaische Zelle hat den Vorteil, dass das verwendete photovoltaisch aktive Halbleitermaterial auch nach dem Einbringen von Siliziumtellurid thermodynamisch stabil ist. Ferner weist die erfindungsgemäße photovoltaische Zelle einen hohen Wirkungsgrad (bis zu 60%) auf, da durch das Siliziumtellurid SiaTeb Zwi- schenniveaus in der Energielücke des photovoltaisch aktiven Halbleitermaterials er¬ zeugt werden. Ohne Zwischenniveau können nur solche Photonen Elektronen oder Ladungsträger vom Valenzband in das Leitungsband heben, die mindestens die Ener¬ gie der Energielücke aufweisen. Photonen höherer Energie tragen auch zum Wir¬ kungsgrad bei, wobei der Überschuss an Energie bzgl. der Bandlücke als Wärme ver¬ loren geht. Mit einem Zwischenniveau, das bei dem für die vorliegende Erfindung ver- wendeten Halbleitermaterial vorhanden ist und das teilweise besetzt werden kann, können mehr Photonen zur Anregung beitragen.The photovoltaic cell according to the invention has the advantage that the photovoltaically active semiconductor material used is thermodynamically stable even after introduction of silicon telluride. Furthermore, the photovoltaic cell according to the invention has a high degree of efficiency (up to 60%) since the silicon telluride Si a Te b generates intermediate levels in the energy gap of the photovoltaically active semiconductor material. Without intermediate level, only such photons can be electrons or Lift charge carriers from the valence band into the conduction band, which have at least the energy gap energy. Photons of higher energy also contribute to the efficiency, the excess of energy with respect to the band gap being lost as heat. With an intermediate level present in the semiconductor material used for the present invention, which can be partially occupied, more photons can contribute to the excitation.
Die erfindungsgemäße photovoltaische Zelle ist so aufgebaut, dass sie ein p-dotiertes und ein n-dotiertes Halbleitermaterial enthält, wobei diese beiden Halbleitermaterialien aneinander grenzen, um einen p-n-Übergang zu bilden. Dabei besteht sowohl das p- als auch das n-dotierte Halbleitermaterial weitgehend aus Mischverbindungen der Formel (I), wobei das Material ferner mit Donatorionen in dem p-dotierten Halbleiterma¬ terial und Akzeptorionen in dem n-dotierten Halbleitermaterial dotiert ist.The photovoltaic cell of the present invention is constructed to include a p-doped and an n-doped semiconductor material, these two semiconductor materials adjoining each other to form a p-n junction. In this case, both the p- and the n-doped semiconductor material largely consists of mixed compounds of the formula (I), wherein the material is further doped with donor ions in the p-doped Halbleiterma¬ material and acceptor ions in the n-doped semiconductor material.
Vorzugsweise enthält das p-dotierte Halbleitermaterial mindestens ein Element aus der Gruppe As und P mit einem Atomkonzentrationsanteil von bis zu 0,1 At-% und das n-dotierte Halbleitermaterial mindestens ein Element aus der Gruppe AI, In und Ga mit einem Atomkonzentrationsanteil von bis zu 0,5 At-%. Bevorzugte Dotierelemente sind Aluminium und Phosphor.Preferably, the p-doped semiconductor material contains at least one element from the group As and P with an atomic concentration of up to 0.1 at% and the n-doped semiconductor material at least one element from the group AI, In and Ga with an atomic concentration of up to to 0.5 at%. Preferred dopants are aluminum and phosphorus.
Gemäß einer bevorzugten Ausführungsform der erfindungsgemäßen photovoltaischen Zelle umfasst diese ein Substrat, insbesondere ein elektrisch leitfähiges Substrat, eine p-Schicht aus dem p- dotierten Halbleitermaterial mit einer Dicke von 0,1 bis 10 μm, bevorzugt 0,3 bis 3 μm und eine n-Schicht aus dem n-dotierten Halbleitermaterial mit einer Dicke von 0,1 bis 10 μm, bevorzugt 0,3 bis 3 μm. Vorzugsweise ist das Substrat eine flexible Metallfolie oder ein flexibles Metallblech. Durch die Kombination aus ei¬ nem flexiblen Substrat mit dünnen photovoltaisch aktiven Schichten ergibt sich der Vorteil, dass keine aufwendigen und damit teuren Auflager zur Halterung der die erfin¬ dungsgemäßen photovoltaischen Zellen enthaltenden Solarmodule eingesetzt werden müssen. Bei unflexiblen Substraten wie Glas oder Silizium müssen Windkräfte durch aufwendige Tragekonstruktionen abgefangen werden, um ein Brechen der Solarmodu¬ le zu vermeiden. Ist dagegen eine Verwindung durch Flexibilität möglich, so können sehr einfache und preiswerte Tragkonstruktionen eingesetzt werden, die nicht verwin- dungssteif sein müssen. Als bevorzugtes flexibles Substrat wird bei der vorliegenden Erfindung insbesondere ein Edelstahlblech verwendet.According to a preferred embodiment of the photovoltaic cell according to the invention, this comprises a substrate, in particular an electrically conductive substrate, a p-layer of the p-doped semiconductor material having a thickness of 0.1 to 10 .mu.m, preferably 0.3 to 3 .mu.m, and an n Layer of the n-doped semiconductor material having a thickness of 0.1 to 10 .mu.m, preferably 0.3 to 3 microns. Preferably, the substrate is a flexible metal foil or a flexible metal sheet. The combination of a flexible substrate with thin photovoltaically active layers affords the advantage that no costly and therefore expensive supports have to be used to hold the solar modules containing the photovoltaic cells according to the invention. In the case of inflexible substrates such as glass or silicon, wind forces have to be absorbed by complex supporting constructions in order to avoid breakage of the solar module. If, on the other hand, twisting is possible by means of flexibility, it is possible to use very simple and inexpensive supporting structures which do not have to be torsionally stiff. As the preferred flexible substrate, a stainless steel sheet is particularly used in the present invention.
Die Erfindung bezieht sich weiterhin auf ein Verfahren zur Herstellung einer erfin¬ dungsgemäßen photovoltaischen Zelle, umfassend das Beschichten eines Substrats mit mindestens jeweils einer Schicht aus dem p-dotierten Halbleitermaterial und einer Schicht aus dem n-dotierten Halbleitermaterial, wobei die Schichten eine Dicke von 0,1 bis 10 μm, vorzugsweise von 0,3 bis 3 μm aufweisen. Das Beschichten des Substrats mit der p- oder n-Schicht umfasst dabei vorzugsweise mindestens ein Abscheidungsverfahren ausgewählt aus der Gruppe Sputtern, Laser- ablation, elektrochemisches Abscheiden oder stromloses Abscheiden. Durch das je- weilige Abscheidungsverfahren kann das bereits p- oder n-dotierte Halbleitermaterial mit Mischverbindungen der Formel (I) als Schicht auf das Substrat aufgebracht wer¬ den. Alternativ dazu kann eine Schicht aus dem Halbleitermaterial zunächst ohne p- oder n-Dotierung durch das Abscheidungsverfahren erzeugt werden und diese Schicht anschließend p- oder n-dotiert werden. Das erfindungsgemäße Einbringen von Silizium in Form von Siliziumtellurid wird (falls die jeweilige durch eines der oben genannten Abscheidungsverfahren hergestellte Schicht noch nicht entsprechend ausgebildet ist) vorzugsweise im Anschluss an die Durchführung des Abscheidungsverfahrens (und gegebenenfalls an die p- oder n-Dotierung) durchgeführt.The invention further relates to a method for producing a photovoltaic cell according to the invention, comprising coating a substrate with at least one respective layer of the p-doped semiconductor material and a layer of the n-doped semiconductor material, the layers having a thickness of 0 , 1 to 10 microns, preferably from 0.3 to 3 microns. The coating of the substrate with the p or n layer preferably comprises at least one deposition method selected from the group sputtering, laser ablation, electrochemical deposition or electroless deposition. By means of the respective deposition method, the already p- or n-doped semiconductor material with mixed compounds of the formula (I) can be applied to the substrate as a layer. Alternatively, a layer of the semiconductor material may be first generated without p- or n-doping by the deposition process and this layer then p- or n-doped. The introduction of silicon in the form of silicon telluride according to the invention is (if the respective layer produced by one of the abovementioned deposition methods has not yet been formed accordingly) preferably carried out subsequent to the performance of the deposition process (and optionally to the p- or n-doping).
Ein mögliches Abscheidungsverfahren ist das Beschichten durch Sputtern. Sputtern bezeichnet das Herausschlagen von Atomen aus einem als Elektrode dienenden Sput- ter-Target durch beschleunigte Ionen und die Deposition des herausgeschlagenen Ma¬ terials auf einem Substrat (z.B. Edelstahl). Zum Beschichten eines Substrats bei der vorliegenden Erfindung werden zum Sputtern z.B. Sputter-Targets enthaltend Zink, Mangan, Tellur und Silizium durch Zusammenschmelzen der Bestandteile hergestellt oder einzelne Bestandteile des Halbleitermaterials werden nacheinander auf das Sub¬ strat gesputtert und anschließend auf eine Temperatur von 400 bis 9000C erwärmt.One possible deposition method is sputter coating. Sputtering refers to the ejection of atoms from a sputtering target serving as an electrode by accelerated ions and the deposition of the ejected material on a substrate (eg stainless steel). For coating a substrate in the present invention, for example, sputtering targets containing zinc, manganese, tellurium and silicon are produced by fusing together the constituents or individual constituents of the semiconductor material are sputtered onto the substrate one after the other and then to a temperature of 400 to 900 0 C heated.
Vorzugsweise werden zum Herstellen des Sputter-Targets Zink, Mangan, Tellur und Silizium in einer Reinheit von mindestens 99,5 % eingesetzt. Zink, Mangan, Tellur und Siliziumtellurid (SiaTeb) werden z.B. in einer entwässerten Quarzröhre unter Vakuum bei Temperaturen von 1.200 bis 1.4000C verschmolzen. Beim Herstellen des Sputter- Targets werden vorzugsweise Dotierelemente für eine p- oder n-Dotierung in das Sput- ter-Target eingebracht. Die Dotierelemente, bevorzugt Aluminium zur n-Leitung und Phosphor zur p-Leitung, werden demnach dem Sputter-Target von vornherein zuge¬ fügt. Die Verbindungen AITe bzw. Zn3P2 sind so temperaturstabil, dass sie den Sputter- Prozess ohne wesentliche Stöchiometrie-Änderung überstehen. Auf das Substrat wird dann zunächst eine Schicht mit einer Dotierung aufgesputtert und direkt darauf eine weitere Schicht mit der entgegengesetzten Dotierung.Preferably, zinc, manganese, tellurium and silicon in a purity of at least 99.5% are used to produce the sputtering target. Zinc, manganese, tellurium and silicon telluride (Si a Te b ) are fused in a dehydrated quartz tube under vacuum at temperatures of 1200 to 1400 0 C, for example. When producing the sputtering target, doping elements for a p-type or n-type doping are preferably introduced into the sputtering target. The doping elements, preferably aluminum for n-conduction and phosphorus for p-conduction, are accordingly added to the sputtering target from the outset. The compounds AITe or Zn 3 P 2 are so temperature stable that they survive the sputtering process without significant change in stoichiometry. A layer with a doping is then sputtered onto the substrate and immediately thereafter a further layer with the opposite doping.
Ein weiteres bevorzugtes erfindungsgemäßes Abscheidungsverfahren ist das elektro¬ chemische Abscheiden von Zn1^MnxTe auf dem elektrisch leitfähigen Substrat. Die elektrochemische Abscheidung von ZnTe ist beschrieben in „Thin films of ZnTe e- lectrodeposited on stainless steel", A.E. Rakhsan u. B. Pradup, Appl. Phys. A (2003), Pub online Dec. 19, 2003, Springer- Verlag; „Electrodeposition of ZnTe for photovoltaic alls", B. Bozzini et al., Thin Solid Films, 361-362, (2000) 288-295; „Electrochemical deposition of ZnTe Thins films", T. Mahalingam et al., Semicond. Sei. Technol. 17 (2002) 469-470; "Electrodeposition of Zn-Te Semiconductor Film from Acidic Aqueous Solution", R. Ichino et al., Second Internat. Conference on Processing Materials for Properties, The Minerals, Metals & Materials Society, 2000 und in US-PS 4,950,615, nicht hingegen die elektrochemische Abscheidung von gemischten Zn/Mn/Te- Schichten.Another preferred deposition method according to the invention is the electrochemical deposition of Zn 1 Mn x Te on the electrically conductive substrate. The electrochemical deposition of ZnTe is described in "Thin Films of ZnTe Electrodeposited on Stainless Steel", AE Rakhsan and Pradup, Appl. Phys. A (2003), Pub., Online, Dec. 19, 2003, Springer-Verlag; "Electrodeposition of ZnTe for photovoltaic alls", B. Bozzini et al., Thin Solid Films, 361-362, (2000) 288-295; "Electrochemical Deposition of ZnTe Thins films ", T. Mahalingam et al., Semicond., See Technol., 17 (2002) 469-470;" Electrodeposition of Zn-Te Semiconductor Film from Acidic Aqueous Solution ", R. Ichino et al., Second Internat. Conference on Processing Materials for Properties, The Minerals, Metals & Materials Society, 2000, and U.S. Patent 4,950,615, but not the electrochemical deposition of mixed Zn / Mn / Te layers.
Gegenstand eines erfindungsgemäßen Verfahrens ist es ferner, Zn^M^Te-Schichten stromlos abzuscheiden, indem in Gegenwart des Substrats eine wässrige Lösung, die Zn2+, Mn2+ sowie TeO3 2 -lonen enthält, bei Temperaturen von 30 bis 900C mit hy- pophosphoriger Säure (H3PO2) als Reduktionsmittel vernetzt wird. Durch die hy- pophosphorige Säure wird TeO3 2" zu Te2" reduziert. Damit sind auch Abscheidungen auf elektrisch nicht leitenden Substraten möglich.Subject of a procedure according to the invention, it is further to deposit Zn ^ M ^ Te layers normally by in the presence of the substrate contains an aqueous solution containing Zn 2+, Mn 2+ and TeO 3 2 ions, at temperatures of 30 to 90 0 C is crosslinked with hypophosphorous acid (H 3 PO 2 ) as a reducing agent. The hypophosphorous acid reduces TeO 3 2 " to Te 2" . This also depositions on electrically non-conductive substrates are possible.
Je nach Abscheidungsverfahren sind noch Nachbehandlungen notwendig, um Silizium- tellurid in die Schichten einzubauen, teilweise auch um die Dotierstoffe einzubringen.Depending on the deposition process, aftertreatments are still necessary to incorporate silicon telluride into the layers, in some cases also to introduce the dopants.
Gemäß einer bevorzugten Ausführungsform der vorliegenden Erfindung weist das er¬ findungsgemäße Verfahren folgende Verfahrensschritte auf:According to a preferred embodiment of the present invention, the method according to the invention comprises the following method steps:
a) Beschichten des Substrats mit einer ersten Schicht aus Zn1^MnxTe, b) Einbringen von Silizium in die erste Schicht zum Herstellen von Mischverbin¬ dungen der Formel (I), c) Erzeugen einer p- oder einer n-Dotierung mit Donatoratomen oder Akzeptor- atomen, d) Beschichten der ersten Schicht mit einer zweiten Schicht aus Zn1-xMnxTe, e) Einbringen von Silizium in die zweite Schicht zum Herstellen von Mischver¬ bindungen in der Formel (I), f) Erzeugen einer n- oder p-Dotierung mit Akzeptoratomen oder Donatoratomen und g) Aufbringen einer elektrisch leitfähigen transparenten Schicht und einer Schutzschicht auf die zweite Schicht.a) coating the substrate with a first layer of Zn 1 Mn x Te, b) introducing silicon into the first layer for producing Mischverbin¬ compounds of formula (I), c) generating a p- or an n-doping with D donating atoms or acceptor atoms, d) coating the first layer with a second layer of Zn 1-x Mn x Te, e) introducing silicon into the second layer to produce mixed compounds in the formula (I), f) generating n- or p-doping with acceptor atoms or donor atoms; and g) applying an electrically conductive transparent layer and a protective layer to the second layer.
In Schritt a) wird das elektrisch leitfähige Substrat z.B. durch Sputtem, elektrochemi- sehe Abscheidung oder stromlose Abscheidung mit einer ersten Schicht aus Zn1^MnxTe beschichtet. Bei dem Substrat handelt es sich vorzugsweise um ein Metall¬ blech oder eine Metallfolie.In step a), the electrically conductive substrate is coated, for example by sputtering, electrochemical deposition or electroless deposition, with a first layer of Zn 1 Mn x Te. The substrate is preferably a metal sheet or a metal foil.
Danach wird in Schritt b) in diese erste Schicht Silizium eingebracht, um Mischverbin- düngen der Formel (I) herzustellen. Das Einbringen von Silizium erfolgt z.B. dadurch, dass Si2Te3 durch Sputtem auf die erste Schicht aufgebracht wird und anschließend durch eine thermische Nachbehandlung bei 600 bis 12000C, vorzugsweise 800 bis 10000C, eine Mischkristallisation und damit die gewünschte Zusammensetzung er¬ reicht wird.Thereafter, silicon is introduced into this first layer in step b) to produce mixed compounds of the formula (I). The introduction of silicon takes place, for example, by applying Si 2 Te 3 to the first layer by sputtering and then by a thermal post-treatment at 600 to 1200 0 C, preferably 800 to 1000 0 C, a mixed crystallization and thus the desired composition er¬ is sufficient.
In Schritt c) erfolgt anschließend das Erzeugen einer p- oder n-Dotierung durch Dotie¬ ren mit Donatoratomen oder Akzeptoratomen. Beispielsweise wird die erste Schicht entweder mit Phosphor (beispielsweise aus PCI3) zum p-Leiter oder mit Aluminium (beispielsweise aus AICI3) zum n-Leiter dotiert.In step c), a p- or n-doping is then generated by doping with donor atoms or acceptor atoms. For example, the first layer is doped either with phosphorus (for example from PCI 3 ) to the p-type conductor or with aluminum (for example from AICI 3 ) to the n-type conductor.
In Schritt d) wird sodann die zweite Schicht aus Zn1-xMnxTe auf der ersten Schicht ab¬ geschieden. Dazu kann beispielsweise das gleiche Abscheidungsverfahren wie in Schritt a) dienen.In step d), the second layer of Zn 1 -x Mn x Te is then deposited on the first layer. This can be done, for example, the same deposition method as in step a).
In Schritt e) wird wie anhand der ersten Schicht für Schritt b) beschrieben Silizium in die zweite Schicht eingebracht.In step e), silicon is introduced into the second layer as described with reference to the first layer for step b).
Die in Schritt f) erzeugte Dotierung ist der in Schritt c) erzeugten Dotierung entgegen¬ gesetzt, so dass eine Schicht eine p-Dotierung und die andere Schicht eine n- Dotierung aufweist.The doping generated in step f) is opposed to the doping generated in step c), so that one layer has a p-type doping and the other layer has an n-type doping.
Schließlich werden in Schritt g) eine elektrisch leitfähige transparente Schicht und eine Schutzschicht auf die zweite Schicht aufgebracht. Die elektrisch leitfähige transparente Schicht kann beispielsweise eine Schicht aus Indium-Zinn-Oxid oder Aluminium-Zink- Oxid sein. Sie trägt ferner vorzugsweise Leiterbahnen für die elektrische Kontaktierung der erfindungsgemäßen photovoltaischen Zelle. Die Schutzschicht kann beispielsweise eine Schicht aus SiOx sein, die vorzugsweise durch CVD oder PVD aufgebracht wird. Es kann z.B. eine Schicht aus einem Material als Schutzschicht dienen, das im Stand der Technik für aromadichte Folien (z.B. Kaffeeverpackungen) hergestellt wird.Finally, in step g) an electrically conductive transparent layer and a protective layer are applied to the second layer. The electrically conductive transparent layer may be, for example, a layer of indium tin oxide or aluminum zinc oxide. It also preferably carries printed conductors for the electrical contacting of the photovoltaic cell according to the invention. The protective layer can be, for example, a layer of SiO x , which is preferably applied by CVD or PVD. For example, a layer of a material may serve as a protective layer which is produced in the prior art for aroma-tight films (eg coffee packaging).
Beispiel 1example 1
Entsprechend der StöchiometrieAccording to the stoichiometry
(Zno,5 Mno,5Te)o,95 (Si2Te3)o,o5(Zn o , 5 Mn o , 5 Te) o , 95 (Si 2 Te 3 ) o , o5
wurden 1 ,0350 g Zn; 0,8669 g Mn; 4,0407 g Tellur sowie 0,7316 g Si2Te3 in ein Quarz¬ rohr mit 11 mm Innendurchmesser und ca. 15 cm Länge eingewogen. Das Si2Te3 wur¬ de vorher gesondert hergestellt, indem Silizium und Tellur bei 1.0000C in einem evaku- ierten Quarzrohr zur Reaktion gebracht wurden. Das Rohr wurde unter Vakuum zum Entwässern 10 min lang auf 3000C erhitzt und sodann unter einem Druck kleiner als 0,1 mbar abgeschmolzen. Das Rohr wurde in einem Ofen mit 300°C/h auf 1.3000C aufgeheizt, die Temperatur 10 h bei 1.3000C belassen und der Ofen dann abkühlen gelassen. Während der 10 h bei 1.3000C wurde der Ofen über einen Antrieb 30 mal pro Stunde um seine Längsachse gekippt, um die Schmelze im Quarzrohr zu durchmi- sehen.were 1.050 g Zn; 0.8669 g Mn; 4.0407 g of tellurium and 0.7316 g of Si 2 Te 3 are weighed into a quartz tube with an inner diameter of 11 mm and a length of about 15 cm. The Si 2 Te 3 wur¬ de previously separately prepared by adding silicon and tellurium were taken at 1,000 0 C in an evacua- ierten quartz tube to react. The tube was heated under vacuum to 300 ° C. for 10 minutes to drain and then under a pressure lower than 0.1 mbar melted off. The tube was heated in an oven at 300 ° C / h to 1300 0 C, the temperature for 10 h at 1300 0 C left and then allowed to cool the oven. During the 10 h at 1300 0 C, the furnace was tilted about a drive 30 times per hour about its longitudinal axis to see through the melt in the quartz tube.
Nach dem Abkühlen wurde das Quarzrohr geöffnet und der Schmelzregulus entfernt. Mittels Reflexionsspektroskopie wurden die Anregungsniveaus des Materials bestimmt. Neben der Bandlücke um 2,3 eV wurden noch Energieniveaus bei 0,66 eV; 0,76 eV sowie 0,9 eV gefunden.After cooling, the quartz tube was opened and the melt regulator removed. Reflectance spectroscopy was used to determine the excitation levels of the material. In addition to the band gap around 2.3 eV, energy levels were also found at 0.66 eV; 0.76 eV and 0.9 eV found.
Zur Herstellung einer erfindungsgemäßen photovoltaischen Zelle wird dieses Material auf ein Substrat gesputtert.To produce a photovoltaic cell according to the invention, this material is sputtered onto a substrate.
Beispiel 2Example 2
Zum elektrochemischen Abscheiden wurden Elektrolysen in einem 500 ml Planschliff- Reaktionsgefäß mit Doppelmantel, Innenthermometer und Bodenablassventil durchge- führt. Als Kathode wurde ein Edelstahlblech (100 x 70 x 0.5) verwendet. Die Anode bestand aus MKUSF04 (Graphit).For electrochemical deposition, electrolyses were carried out in a 500 ml flat-bottomed reaction vessel with double jacket, internal thermometer and bottom outlet valve. The cathode used was a stainless steel sheet (100 × 70 × 0.5). The anode consisted of MKUSF04 (graphite).
a) Darstellung von ZnTea) Representation of ZnTe
Es wurden 21 ,35 g ZnSO4 • 7H2O und 55,4 mg Na2TeO3 in destilliertem Wasser gelöst. Diese Lösung wurde mit H2SO4 (2 mol/l) auf pH 2 eingestellt und mit destilliertem Was¬ ser auf 500 ml aufgefüllt (Zn = 0.15 mol/l; Te = 0,5 mmol/l; Zn/Te = 300 / 1). Anschlie¬ ßend wurde die Elektrolyt-Lösung in die Elektrolysezelle gefüllt und auf 800C geheizt. Die Elektrolyse wurde über einen Zeitraum von 30 min. bei einem Strom von 100,0 mA ohne Rühren durchgeführt. Die Abscheidung erfolgte bei einer Kathodenfläche von -50 cm2 (2 mA/cm2). Nach beendeter Elektrolyse wurde die Kathode ausgebaut, mit destil¬ liertem Wasser gespült und getrocknet. Es wurde ein kupferfarbener Film abgeschie¬ den (18,6 mg).21, 35 g of ZnSO 4 • 7H 2 O and 55.4 mg of Na 2 TeO 3 were dissolved in distilled water. This solution was adjusted to pH 2 with H 2 SO 4 (2 mol / l) and made up to 500 ml with distilled water (Zn = 0.15 mol / l, Te = 0.5 mmol / l, Zn / Te = 300) / 1). Anschlie¬ ßend the electrolyte solution was placed in the electrolysis cell and heated to 80 0 C. The electrolysis was over a period of 30 min. at a current of 100.0 mA without stirring. The deposition took place at a cathode area of -50 cm 2 (2 mA / cm 2 ). After completion of the electrolysis, the cathode was removed, rinsed with distilled water and dried. A copper-colored film was abgeschie¬ the (18.6 mg).
b) Darstellung von Zn1^MnxTeb) Representation of Zn 1 ^ Mn x Te
Es wurden 21 ,55 g ZnSO4 • 7H2O (0,15 mol/l), 47,68 g MnSO4 • H2O (0,6 mol/l), 33 g (NH4J2SO4 (0,5 mol/l), 1 g Weinsäure und 55,4 mg Na2TeO3 (0,5 mmol/l) in destilliertem Wasser gelöst. Diese Lösung wurde mit H2SO4 (2 mol/l) auf pH 2 eingestellt und mit destilliertem Wasser auf 500 ml aufgefüllt (Zn / Mn / Te = 300 / 1200 / 1 ). Anschließend wurde die Elektrolyt-Lösung in die Elektrolysezelle gefüllt und auf 80°C geheizt. Die Elektrolyse wurde über einen Zeitraum von 60 min. bei einem Strom von 101 ,3 mA ohne Rühren durchgeführt. Die Abscheidung erfolgte bei einer Kathodenfläche von -50 cm2 ( ~2 mA/cmz). Nach beendeter Elektrolyse wurde die Kathode ausgebaut, mit des¬ tilliertem Wasser gespült und getrocknet. Die Gewichtszunahme beträgt 26,9 mg. Die Abscheidung hat eine tief dunkelbraune Farbe. There were added 21.55 g of ZnSO 4 • 7H 2 O (0.15 mol / L), 47.68 g of MnSO 4 • H 2 O (0.6 mol / L), 33 g of (NH 4 J 2 SO 4 ( 0.5 mol / l), 1 g tartaric acid and 55.4 mg Na 2 TeO 3 (0.5 mmol / l) dissolved in distilled water This solution was adjusted to pH 2 with H 2 SO 4 (2 mol / l) adjusted and made up to 500 ml with distilled water (Zn / Mn / Te = 300/1200/1), then the electrolyte solution was filled into the electrolysis cell and heated to 80 ° C Electrolysis was carried out over a period of 60 min. at a current of 101, 3 mA carried out without stirring. The deposition was carried out at a cathode area of -50 cm 2 (~ 2 mA / cm z ). After completion of the electrolysis, the cathode was removed, rinsed with distilled water and dried. The weight gain is 26.9 mg. The deposit has a deep dark brown color.

Claims

Patentansprüche claims
1. Photovoltaische Zelle mit einem photovoltaisch aktiven Halbleitermaterial, da¬ durch gekennzeichnet, dass das photovoltaisch aktive Halbleitermaterial ein p- oder n-dotiertes Halbleitermaterial mit Mischverbindungen der Formel (I) ist:1. Photovoltaic cell with a photovoltaically active semiconductor material, da¬ characterized in that the photovoltaically active semiconductor material is a p- or n-doped semiconductor material with mixed compounds of the formula (I):
(Zn1-xMnxTe)1.y(SiaTeb)y (I)(Zn 1-x Mn x Te) 1 . y (Si a Te b ) y (I)
mit x = Zahl von 0,01 bis 0,99, y = Zahl von 0,01 bis 0,2, a = Zahl von 1 bis 2 und b = Zahl von 1 bis 3.where x = number from 0.01 to 0.99, y = number from 0.01 to 0.2, a = number from 1 to 2 and b = number from 1 to 3.
2. Photovoltaische Zelle gemäß Anspruch 1 , dadurch gekennzeichnet, dass das p- dotierte Halbleitermaterial mindestens ein Element aus der Gruppe As und P mit einem Atomkonzentrationsanteil von bis zu 0,1 At-% enthält und dass das n- dotierte Halbleitermaterial mindestens ein Element aus der Gruppe AI, In und Ga mit einem Atomkonzentrationsanteil von bis zu 0,5 At-% enthält.2. Photovoltaic cell according to claim 1, characterized in that the p-doped semiconductor material contains at least one element from the group As and P with an atomic concentration of up to 0.1 at% and that the n-doped semiconductor material at least one element the group AI, In and Ga with an atomic concentration of up to 0.5 at%.
3. Photovoltaische Zelle gemäß einem der Ansprüche 1 oder 2, umfassend ein Substrat, eine p-Schicht aus dem p-dotierten Halbleitermaterial mit einer Dicke von 0,1 bis 10 μm und eine n-Schicht aus dem n-dotierten Halbleitermaterial mit einer Dicke von 0,1 bis 10 μm.3. A photovoltaic cell according to any one of claims 1 or 2, comprising a substrate, a p-layer of the p-doped semiconductor material having a thickness of 0.1 to 10 microns and an n-layer of the n-doped semiconductor material having a thickness from 0.1 to 10 μm.
4. Photovoltaische Zelle gemäß Anspruch 3, dadurch gekennzeichnet, dass das Substrat eine flexible Metallfolie oder ein flexibles Metallblech ist.4. Photovoltaic cell according to claim 3, characterized in that the substrate is a flexible metal foil or a flexible metal sheet.
5. Verfahren zur Herstellung einer photovoltaischen Zelle gemäß einem der An¬ sprüche 1 bis 4, gekennzeichnet durch das Beschichten eines Substrats mit min¬ destens jeweils einer Schicht aus dem p-dotierten Halbleitermaterial und einer Schicht aus dem n-dotierten Halbleitermaterial, wobei die Schichten eine Dicke von 0,1 bis 10 μm aufweisen.5. A method for producing a photovoltaic cell according to any one of An¬ claims 1 to 4, characterized by coating a substrate with min¬ least one layer of the p-doped semiconductor material and a layer of the n-doped semiconductor material, wherein the layers have a thickness of 0.1 to 10 microns.
6. Verfahren gemäß Anspruch 5, dadurch gekennzeichnet, dass das Beschichten mindestens ein Abscheidungsverfahren aus der Gruppe Sputtern, Laserablation, elektrochemisches Abscheiden oder stromloses Abscheiden umfasst. 6. The method according to claim 5, characterized in that the coating comprises at least one deposition method from the group sputtering, laser ablation, electrochemical deposition or electroless deposition.
7. Verfahren gemäß Anspruch 6, dadurch gekennzeichnet, dass zum Sputtern ein Sputter-Target enthaltend Zink, Mangan, Tellur und Silizium durch Zusammen¬ schmelzen von Bestandteilen hergestellt wird.7. The method according to claim 6, characterized in that for sputtering a sputtering target containing zinc, manganese, tellurium and silicon by Zusammen¬ melt of constituents is prepared.
8. Verfahren gemäß Anspruch 7, dadurch gekennzeichnet, dass zum Herstellen des Sputter-Targets Zn, Mn, Te und Si in einer Reinheit von mindestens 99,5 % eingesetzt werden und dass Zn, Mn, Te und SiaTeb in einer entwässerten Quarz¬ röhre unter Vakuum bei Temperaturen von 1.200 bis 1.4000C verschmolzen wer¬ den.8. The method according to claim 7, characterized in that for producing the sputtering target Zn, Mn, Te and Si are used in a purity of at least 99.5% and that Zn, Mn, Te and Si a Te b in a dewatered Quartz tube fused under vacuum at temperatures of 1200 to 1400 0 C to the.
9. Verfahren gemäß einem der Ansprüche 7 oder 8, dadurch gekennzeichnet, dass beim Herstellen des Sputter-Targets Dotierelemente für eine p- oder n-Dotierung in das Sputter-Target eingebracht werden.9. The method according to any one of claims 7 or 8, characterized in that doping elements for a p- or n-doping are introduced into the sputtering target in the manufacture of the sputtering target.
10. Verfahren gemäß Anspruch 6, dadurch gekennzeichnet, dass zum stromlosen Abscheiden eine wässrige Lösung, die Zn2+-, Mn2+- und TeO3 2"-lonen enthält, bei einer Temperatur von 30 bis 90°C mit hypophosphoriger Säure H3PO2 als Reduk¬ tionsmittel in Gegenwart des Substrats vernetzt wird.10. The method according to claim 6, characterized in that for electroless deposition, an aqueous solution containing Zn 2+ -, Mn 2+ - and TeO 3 2 " ions, at a temperature of 30 to 90 ° C with hypophosphorous acid H 3 PO 2 is crosslinked as Reduk¬ tion medium in the presence of the substrate.
11. Verfahren gemäß einem der Ansprüche 6 bis 10, gekennzeichnet durch die Ver¬ fahrensschritte:11. The method according to any one of claims 6 to 10, characterized by the Ver¬ process steps:
a) Beschichten des Substrats mit einer ersten Schicht aus Zni-xMnxTe, b) Einbringen von Si in die erste Schicht zum Herstellen von Mischverbindun- gen der Formel (I), c) Erzeugen einer p- oder n-Dotierung mit Donatoratomen oder Akzeptorato¬ men, d) Beschichten der ersten Schicht mit einer zweiten Schicht aus Zn1^MnxTe, e) Einbringen von Silizium in die zweite Schicht zum Herstellen von Mischver- bindungen der Formel (I), f) Erzeugen einer n- oder p-Dotierung mit Akzeptoratomen oder Donatorat¬ omen und g) Aufbringen einer elektrisch leitfähigen transparenten Schicht und einer Schutzschicht auf die zweite Schicht. a) coating the substrate with a first layer of Zni -x Mn x Te, b) introducing Si into the first layer to produce mixed compounds of the formula (I), c) producing a p- or n-doping with donor atoms or acceptorato, d) coating the first layer with a second layer of Zn 1 Mn x Te, e) introducing silicon into the second layer to produce mixed compounds of the formula (I), f) generating an or p-doping with acceptor atoms or donor atoms and g) applying an electrically conductive transparent layer and a protective layer to the second layer.
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