EP1935031A2 - Photovoltaic cell comprising a photovoltaically active semi-conductor material contained therein - Google Patents

Photovoltaic cell comprising a photovoltaically active semi-conductor material contained therein

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Publication number
EP1935031A2
EP1935031A2 EP06793915A EP06793915A EP1935031A2 EP 1935031 A2 EP1935031 A2 EP 1935031A2 EP 06793915 A EP06793915 A EP 06793915A EP 06793915 A EP06793915 A EP 06793915A EP 1935031 A2 EP1935031 A2 EP 1935031A2
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Prior art keywords
formula
photovoltaic cell
semiconductor material
layer
znte
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EP06793915A
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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
    • 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
    • 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
    • H01L31/0272—Selenium or tellurium
    • 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
    • H01L31/0296—Inorganic materials including, apart from doping material or other impurities, only AIIBVI compounds, e.g. CdS, ZnS, HgCdTe
    • 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
    • H01L31/0296—Inorganic materials including, apart from doping material or other impurities, only AIIBVI compounds, e.g. CdS, ZnS, HgCdTe
    • H01L31/02963—Inorganic materials including, apart from doping material or other impurities, only AIIBVI compounds, e.g. CdS, ZnS, HgCdTe characterised by the doping material
    • 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
    • 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
    • H01L31/072—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 heterojunction type
    • 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

Definitions

  • Photovoltaic cell with a photovoltaically active semiconductor material contained therein
  • 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.
  • Most of the technically used solar cells are based on crystalline silicon (monocrystalline or polycrystalline).
  • 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 recombined by different processes and thus deprived of their 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.
  • 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. Würfel or "Increasing the Efficiency of Ideal Solar Cells by Photon Induced Transitions 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 some of the tellurane ions in the anion lattice with the much 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 1-x Mn x Tei -y Oy with y greater than 0.001 are not thermodynamically stable. Upon irradiation for a long time, they decompose 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 2.25 eV at room temperature, would be an ideal semiconductor for the intermediate level technology because of this large band gap.
  • Zinc is readily substituted by magnesium in zinc telluride, with the band gap increasing to about 3.4 eV in MgTe (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 Zn 1- JVIn x Te: nonlinear dependence on compostion and temperature", HC Mertins et al., Semicond Technol. 8 (1993) 1634-1638).
  • a photovoltaic cell usually contains a p-type absorber and an n-type transparent layer of, for example, indium-tin oxide, fluorine-doped tin oxide, antimony-doped zinc oxide or aluminum-doped zinc oxide.
  • x 0.01 to 0.7 metal halides of the metals germanium, tin, antimony, bismuth or copper in proportions of preferably 0.005 to 0.05 moles per mole of telluride are introduced.
  • the partial replacement of tellurium in the semiconductor lattice by the electronegative halide ions causes the formation of the desired stable intermediate energy level in the bandgap.
  • the object of the present invention is to provide a photovoltaic cell with high efficiency and high electric power.
  • a further object of the present invention is to provide a photovoltaic cell with an alternative, 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 wherein the photovoltaically active semiconductor material is a material of the formula (I), of the formula (II) or a combination thereof
  • M n Te m and Me a M b are each a dopant in which M is at least one element selected from the group of silicon, germanium, tin, lead, antimony and bismuth and Me for at least one element selected from the group magnesium and zinc
  • n 1 to 2
  • m 0.5 to 4
  • the invention further relates to a photovoltaically active semiconductor material of the formula (I), the formula (II) or a combination thereof, with
  • the doping agent (M n Te m or Me a M b ) at least one compound selected from the group Si 3 Te 3 , GeTe, SnTe, PbTe, Sb 2 Te 3 , Bi 2 Te 3 , Mg 2 Si, Mg 2 Ge, Mg 2 Sn, Mg 2 Pb, Mg 3 Sb 2 , Mg 3 Bi 2 , ZnSb, Zn 3 Sb 2 and Zn 4 Sb 3 .
  • Sb 2 Te 3 has a band gap of 0.3 eV as a pure substance. If ZnTe is doped with 2 mol% of Sb 2 Te 3 , an absorption at 0.8 eV is found in addition to the band gap of the ZnTe at 2.25 to 2.3 eV.
  • the semiconductor materials used in the photovoltaic cell according to the invention have high Seebeck coefficients of up to 100 ⁇ V / degree with high electrical conductivity. This behavior shows that the new semiconductors can be activated not only visually, but also thermally, thus contributing to a better utilization of light quanta.
  • the photovoltaic cell according to the invention has the advantage that the used photovoltaically active semiconductor material of the formula (I), the formula (II) or a combination thereof is thermodynamically stable. Furthermore, the photovoltaic cells according to the invention have high efficiencies of more than 15%, since an intermediate level in the energy level due to the dopants contained in the semiconductor material. bridge of the photovoltaically active semiconductor material is generated. Without an intermediate level, only such photons can lift electrons or charge carriers from the valence band into the conduction band, which have at least the energy of the energy gap. Higher energy photons also contribute to efficiency, with the excess of energy lost to the bandgap as heat. With the intermediate level present in the semiconductor material used for the present invention, which can be partially filled, more photons can contribute to the excitation.
  • the photovoltaic cell of the present invention is preferably constructed to contain a p-type absorber layer of the material of the formula (I), the formula (II) or a combination thereof. Adjacent to this absorber layer of the p-type semiconductor material is an n-conducting contact layer which is as non-absorbent as possible, preferably an n-conducting transparent layer comprising at least one semiconductor material selected from the group consisting of indium tin oxide, fluorine doped tin oxide and antimony doped contains gallium-doped, indium-doped and aluminum-doped zinc oxide. Incident light generates a positive and a negative charge in the p-type semiconductor layer. The charges diffuse in the p-region. Only when the negative charge reaches the p-n interface can it leave the p-region. A current flows when the negative charge has reached the front contact attached to the contact layer.
  • this comprises an electrically conductive substrate, a p-layer of the inventive semiconductor material of the formula (I) and / or (II) with a thickness of 0.1 to 20 .mu.m, preferably of 0 , 1 to 10 microns, more preferably from 0.3 to 3 microns, and an n-layer of an n-type semiconductor material having a thickness of 0.1 to 20 microns, preferably 0.1 to 10 microns, more preferably 0, 3 to 3 ⁇ m.
  • the substrate is preferably a glass pane coated with an electrically conductive material, a flexible metal foil or a flexible metal sheet.
  • the photovoltaic cell according to the invention preferably contains a layer of molybdenum or tungsten having a preferred thickness of between 0.1 and 2 .mu.m, which is used as barrier layer and for facilitating tion of the exit of the electrons in the absorber and is used as the back contact in the case of glass as a substrate.
  • the invention further relates to a method for producing the photovoltaically active semiconductor material according to the invention and / or a photovoltaic cell according to the invention, comprising the steps:
  • the layer formed from the semiconductor material of the formula Zn 1-x Te JVIg or ZnTe preferably has a thickness of 0.1 microns to 20, preferably from 0.1 to 10 .mu.m, particularly preferably from 0.3 to 3 microns.
  • This layer is preferably produced by at least one deposition process selected from the group sputtering, electrochemical deposition and electroless deposition.
  • Sputtering refers to the knocking out of clusters comprising about 10 to 10,000 atoms from an electrode sputtering target by accelerated ions and the deposition of the knocked-out material onto a substrate.
  • the layers of the semiconductor material of the formula (I) and / or (II) produced according to the method according to the invention are particularly preferably produced by sputtering because sputtered layers have increased qualities.
  • the electrochemical deposition of ZnTe for producing a layer and the subsequent doping of this layer with a dopant for producing a semiconductor material of the formula (I) and / or (II) are also suitable.
  • the introduction of the doping metal during the synthesis of the zinc telluride in evacuated quartz vessels is particularly preferred.
  • the quartz vessel is heated in an oven, first rapidly to about 400 ° C, because below the melting points of Zn and Te no reaction takes place.
  • the temperature is increased more slowly with rates of 20 to 100 ° C / h up to 800 to 1200 ° C, preferably to 1000 to 1100 ° C.
  • the formation of the solid state takes place.
  • the time required for this is 1 to 100 hours, preferably 5 to 50 hours.
  • the cooling takes place.
  • the content of the quartz vessel is crushed under moisture exclusion to particle sizes of 0.1 to 1 mm and these particles are then reduced, for example in a ball mill to particle sizes of 1 to 30 microns, preferably 2 to 20 microns.
  • sputtering targets are prepared by hot pressing at 300 to 1200 ° C, preferably 400 to 700 ° C and pressures of 5 to 500 MPa, preferably 20 to 200 MPa. The pressing times are from 0.2 to 10 h, preferably 1 to 3 h.
  • a photovoltaically active semiconductor material and / or a photovoltaic cell is a sputtering target of the formula (Zn 1-x Mg x Te) i -y (M n Te m ) y and / or (ZnTe ) i. y (Me a M b ) y produced by
  • a sputtering target of the formula Zn 1- JVIg x Te and / or ZnTe is prepared by a) reacting Zn, Te and optionally Mg in evacuated Quartz tubes at 800 to 1200 ° C, preferably at 1000 to 1100 ° C, within 1 to 100 h, preferably within 5 to 50 h, to obtain a material, b) grinding the material after cooling with substantial exclusion of atmospheric oxygen and Moisture to a powder with particle sizes of 1 to 30 .mu.m, preferably from 2 to 20 .mu.m, and c) hot pressing of the powder at temperatures of 300 to 1200 ° C, preferably from 400 to 700 ° C, at pressures of 5 to 500 MPa, preferably from 20 to 200 MPa at press times of 0.2 to 10 h, preferably from 1 to 3 h.
  • the dopants M n Te m and Me a M b can be introduced after sputtering in the Zn 1 JVIg x Te and / or ZnTe.
  • the material obtained in step a) is ground in step b) with the dopant M n Te m or Me a M b .
  • part of the dopant can react with the zinc telluride in the form of a reaction grinding and be incorporated into the host lattice.
  • the doped material of the formula (I) or (II) or combinations thereof according to the invention then forms during the hot pressing in step c)
  • the photovoltaic cell according to the invention is completed by the method according to the invention.
  • compositions given in the result table were prepared in evacuated quartz tubes by reaction of the elements in the presence of the doping metals.
  • the elements were weighed in a purity better than 99.99% in quartz tubes, the residual moisture removed by heating in vacuo and the tubes melted in vacuo.
  • the tubes were heated from room temperature to 1 100 ° C within 20 h and the temperature then left at 1100 ° C for 10 h. The oven was then switched off and allowed to cool.
  • the Telluride so prepared were crushed in an agate mortar to powder with particle sizes below 30 microns. This powder was pressed at room temperature under a pressure of 3000 kp / cm 2 to 13 mm diameter disks.
  • compositions from the result table are examples of combinations of semiconductor materials according to the invention of the formula (I) and of the formula (II) and can be described by the formula (III):

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Photovoltaic Devices (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

The invention relates to a photovoltaic cell comprising a photovoltaically active semi-conductor material. The photovoltaically active semi-conductor material is a material of formula (I), formula (II) or a combination therefrom, comprising (I) (Zn1-xMgxTe)1-y(MnTem)y and (II) (ZnTe)1-y(MeaMb)y, whereby MnTem and MeaMb is a doping agent, wherein M represents at least one element selected from the groups Si, Ge, Sn, Pb, Sb and Bi and Me represents at least one element selected from the groups Mg and Zn, wherein x = 0 - 0,5 y = 0,0001 - 0,05 n = 1 - 2 m = 0,5 - 4 a = 1 - 5 and b = 1 - 3.

Description

Photovoltaische Zelle mit einem darin enthaltenen photovoltaisch aktiven HalbleitermaterialPhotovoltaic cell with a photovoltaically active semiconductor material contained therein
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. Die meisten der technisch genutzten Solarzellen basieren auf kristallinem Silizium (ein- oder polykristallin). In einer Grenzschicht zwischen p- und n-leitendem Silizium regen einfallende Photonen Elektronen des Halbleiters an, so dass sie vom Valenzband 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. Most of the technically used solar cells are based on crystalline silicon (monocrystalline or polycrystalline). In a boundary layer between p- and n-conducting 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 Wirkungsgrad von circa 15%, weil ein Teil der Ladungsträger durch verschiedene Prozesse re- kombiniert 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 recombined by different processes and thus deprived of their use.
Aus DE 102 23 744 A1 sind alternative photovoltaisch aktive Materialien und diese enthaltende Photovoltaikzellen bekannt, die den Wirkungsgrad herabsetzende Verlustmechanismen in einem verringerten Maße aufweisen.From DE 102 23 744 A1 alternative photovoltaically active materials and photovoltaic cells containing them are known, which have the efficiency reducing loss mechanisms 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 Leitungsband 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 Energielücken in so genannten Tandemzellen wurden vorgeschlagen, um höhere Wirkungsgrade 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 Transitions 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. Würfel or "Increasing the Efficiency of Ideal Solar Cells by Photon Induced Transitions 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 Cdi.yMnyOχTei-x oder an Zn1-xMnxOyTei-y nachgewiesen. Dies ist beschrieben in "Band anticrossing in group II-OXVI1-X highly mismatched alloys: Cdi.yMnyOxTei-x 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 M-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 wesentlich elektronegativere Sauerstoffion ersetzt wird. Dabei wurde Tellur durch Ionenimplantation in dünnen Filmen durch Sauerstoff ersetzt. Ein wesentlicher Nachteil dieser Stoffklasse besteht darin, dass die Löslichkeit des Sauerstoffs im Halbleiter äußerst gering ist. Daraus folgt, dass beispielsweise die Verbindungen Zn1-xMnxTei-yOy mit y größer als 0,001 thermodynamisch nicht stabil sind. Bei Bestrahlung über längere Zeit zerfallen 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 have been detected, for example, the system Cdi.yMnyOχTei -x or Zn 1-x Mn x OyTei -y. This is described in "Band anticrossing in group II-O X VI 1-X highly mismatched alloys: Cdi.yMn y O x Tei -x 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 MO-VI 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 some of the tellurane ions in the anion lattice with the much more electronegative oxygen ion. In this case, 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 1-x Mn x Tei -y Oy with y greater than 0.001 are not thermodynamically stable. Upon irradiation for a long time, they decompose 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 2,25 eV aufweist, wäre wegen dieser großen Bandlücke ein idealer Halbleiter für die Zwischenniveau- technologie. Zink lässt sich gut in Zinktellurid kontinuierlich durch Magnesium substituieren, wobei die Bandlücke auf circa 3,4 eV bei MgTe 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 Zn1-JVInxTe: 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 2.25 eV at room temperature, would be an ideal semiconductor for the intermediate level technology because of this large band gap. Zinc is readily substituted by magnesium in zinc telluride, with the band gap increasing to about 3.4 eV in MgTe (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 Zn 1- JVIn x Te: nonlinear dependence on compostion and temperature", HC Mertins et al., Semicond Technol. 8 (1993) 1634-1638).
Eine photovoltaische Zelle enthält üblicherweise einen p-leitenden Absorber und eine n-leitende transparente Schicht zum Beispiel aus Indium-Zinn-Oxid, fluordotiertem Zinnoxid, antimondotiertem Zinkoxid oder aluminiumdotiertem Zinkoxid.A photovoltaic cell usually contains a p-type absorber and an n-type transparent layer of, for example, indium-tin oxide, fluorine-doped tin oxide, antimony-doped zinc oxide or aluminum-doped zinc oxide.
Ein Absorber mit einem Zwischenniveau in der Energielücke wird zum Beispiel erhalten, indem in ein Halbleitermaterial der Formel ZnTe und/oder Zn1-xMnxTe mit x = 0,01 bis 0,7 Metallhalogenide der Metalle Germanium, Zinn, Antimon, Bismut oder Kupfer in Anteilen von bevorzugt 0,005 bis 0,05 Mol pro Mol Tellurid eingebracht werden. Offensichtlich bewirkt der teilweise Ersatz von Tellur im Halbleitergitter durch die elekt- ronegativeren Halogenidionen die Ausbildung des gesuchten stabilen Zwischenener- gieniveaus in der Bandlücke.An absorber with an intermediate level in the energy gap is obtained, for example, by placing in a semiconductor material of the formula ZnTe and / or Zn 1-x Mn x Te where x = 0.01 to 0.7 metal halides of the metals germanium, tin, antimony, bismuth or copper in proportions of preferably 0.005 to 0.05 moles per mole of telluride are introduced. Obviously, the partial replacement of tellurium in the semiconductor lattice by the electronegative halide ions causes the formation of the desired stable intermediate energy level in the bandgap.
Die Aufgabe der vorliegenden Erfindung besteht darin, eine photovoltaische Zelle mit einem hohen Wirkungsgrad und einer hohen elektrischen Leistung bereitzustellen. Weiterhin ist es Aufgabe der vorliegenden Erfindung, insbesondere eine photovoltaische Zelle mit einem alternativen, thermodynamisch 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 high efficiency and high electric power. A further object of the present invention is to provide a photovoltaic cell with an alternative, 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 einem photovoltaisch aktiven Halbleitermaterial, wobei das photovoltaisch aktive Halblei- termaterial ein Material der Formel (I), der Formel (II) oder einer Kombination daraus ist, mitThis object is achieved according to the invention by a photovoltaic cell with a photovoltaically active semiconductor material, wherein the photovoltaically active semiconductor material is a material of the formula (I), of the formula (II) or a combination thereof
(I) (Zn1-xMgxTe)i-y(MnTem)y und(I) (Zn 1-x Mg x Te) i -y (M n Te m) and y
(II) (ZnTe)i-y(MeaMb)y, wobei(II) (ZnTe) i -y (Me a M b ) y , where
MnTem und MeaMb jeweils ein Dotiermittel ist, in dem M für mindestens ein Element ausgewählt aus der Gruppe Silizium, Germanium, Zinn, Blei, Antimon und Bismut steht und Me für mindestens ein Element ausgewählt aus der Gruppe Magnesium und Zink steht, mit x = 0 bis 0,5 y = 0,0001 bis 0,05 n = 1 bis 2 m = 0,5 bis 4 a = 1 bis 5 b = 1 bis 3.M n Te m and Me a M b are each a dopant in which M is at least one element selected from the group of silicon, germanium, tin, lead, antimony and bismuth and Me for at least one element selected from the group magnesium and zinc where x = 0 to 0.5 y = 0.0001 to 0.05 n = 1 to 2 m = 0.5 to 4 a = 1 to 5 b = 1 to 3.
Die Erfindung bezieht sich weiterhin auf ein photovoltaisch aktives Halbleitermaterial der Formel (I), der Formel (II) oder einer Kombination daraus, mitThe invention further relates to a photovoltaically active semiconductor material of the formula (I), the formula (II) or a combination thereof, with
(I) (Zn1-xMgxTe)i-y(MnTem)y und(I) (Zn 1-x Mg x Te) i -y (M n Te m) and y
(II) (ZnTe)i.y(MeaMb)y, wobei(II) (ZnTe) i. y (Me a M b ) y , where
MnTem und MeaMb jeweils ein Dotiermittel ist, in dem M für mindestens ein Element ausgewählt aus der Gruppe Silizium, Germanium, Zinn, Blei, Antimon und Bismut steht und Me für mindestens ein Element ausgewählt aus der Gruppe Magnesium und Zink steht, mit x = 0 bis 0,5 y = 0,0001 bis 0,05 n = 1 bis 2 m = 0,5 bis 4 a = 1 bis 5 und b = 1 bis 3.M n Te m and Me a M b are each a dopant in which M is at least one element selected from the group of silicon, germanium, tin, lead, antimony and bismuth and Me for at least one element selected from the group magnesium and zinc where x = 0 to 0.5 y = 0.0001 to 0.05 n = 1 to 2 m = 0.5 to 4 a = 1 to 5 and b = 1 to 3.
Völlig überraschend wurde gefunden, dass auf den Einbau von Halogenidionen verzichtet werden kann, wenn man Telluride der Formel (I) oder (II) oder Kombinationen daraus einsetzt.Quite surprisingly, it has been found that the incorporation of halide ions can be dispensed with if tellurides of the formula (I) or (II) or combinations thereof are used.
Es wird vermutet, dass sich die genannten Telluride mit den Metallionen M = Si, Ge, Sn, Pb, Sb und/oder Bi im Kristallgitter so verhalten, dass sie in der Nähe von Zn2+- lonen negativ und in der Nähe von Te2~lonen positiv polarisiert werden, wie beispielsweiseIt is assumed that the tellurides mentioned behave in the crystal lattice with the metal ions M = Si, Ge, Sn, Pb, Sb and / or Bi in such a way that they are negative in the vicinity of Zn 2+ ions and in the vicinity of Te 2 ~ ions are positively polarized, such as
2+ δ - δ+ 2-2+ δ - δ + 2
Zn Sb Sb TeZn Sb Sb Te
und dass sich dadurch das gesuchte Zwischenenergieniveau ausbildet. Magnesium scheint diesen Effekt noch zu verstärken, weil es elektronegativer als Zink ist.and that thereby forms the desired intermediate energy level. Magnesium seems to amplify this effect because it is more electronegative than zinc.
Gemäß einer bevorzugten Ausführungsform der vorliegenden Erfindung ist das Do- tiermittel (MnTem oder MeaMb) mindestens eine Verbindung ausgewählt aus der Gruppe Si3Te3, GeTe, SnTe, PbTe, Sb2Te3, Bi2Te3, Mg2Si, Mg2Ge, Mg2Sn, Mg2Pb, Mg3Sb2, Mg3Bi2, ZnSb, Zn3Sb2 und Zn4Sb3.According to a preferred embodiment of the present invention, the doping agent (M n Te m or Me a M b ) at least one compound selected from the group Si 3 Te 3 , GeTe, SnTe, PbTe, Sb 2 Te 3 , Bi 2 Te 3 , Mg 2 Si, Mg 2 Ge, Mg 2 Sn, Mg 2 Pb, Mg 3 Sb 2 , Mg 3 Bi 2 , ZnSb, Zn 3 Sb 2 and Zn 4 Sb 3 .
Sb2Te3 weist als reiner Stoff beispielsweise eine Bandlücke von 0,3 eV auf. Dotiert man ZnTe mit 2 Mol-% Sb2Te3, so findet man zusätzlich zu der Bandlücke des ZnTe bei 2,25 bis 2,3 eV eine Absorption bei 0,8 eV.For example, Sb 2 Te 3 has a band gap of 0.3 eV as a pure substance. If ZnTe is doped with 2 mol% of Sb 2 Te 3 , an absorption at 0.8 eV is found in addition to the band gap of the ZnTe at 2.25 to 2.3 eV.
Es sind auch Kombinationen der genannten Dotiermittel möglich.Combinations of the mentioned dopants are also possible.
Die in der erfindungsgemäßen photovoltaischen Zelle eingesetzten Halbleitermaterialien weisen überraschenderweise bei hoher elektrischer Leitfähigkeit hohe Seebeck- Koeffizienten bis zu 100 μV/Grad auf. Dieses Verhalten zeigt, dass die neuen Halbleiter nicht nur optisch, sondern auch thermisch aktiviert werden können und damit zur besseren Nutzung von Lichtquanten beitragen.Surprisingly, the semiconductor materials used in the photovoltaic cell according to the invention have high Seebeck coefficients of up to 100 μV / degree with high electrical conductivity. This behavior shows that the new semiconductors can be activated not only visually, but also thermally, thus contributing to a better utilization of light quanta.
Die erfindungsgemäße photovoltaische Zelle hat den Vorteil, dass das verwendete photovoltaisch aktive Halbleitermaterial der Formel (I), der Formel (II) oder einer Kombination daraus thermodynamisch stabil ist. Ferner weisen die erfindungsgemäßen photovoltaischen Zellen hohe Wirkungsgrade oberhalb von 15 % auf, da durch die in dem Halbleitermaterial enthaltenen Dotiermittel ein Zwischenniveau in der Energielü- cke des photovoltaisch aktiven Halbleitermaterials erzeugt wird. Ohne Zwischenniveau können nur solche Photonen Elektronen oder Ladungsträger vom Valenzband in das Leitungsband heben, die mindestens die Energie der Energielücke aufweisen. Photonen höherer Energie tragen auch zum Wirkungsgrad bei, wobei der Überschuss an Energie bezüglich der Bandlücke als Wärme verloren geht. Mit dem Zwischenniveau, das bei dem für die vorliegende Erfindung verwendeten 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 used photovoltaically active semiconductor material of the formula (I), the formula (II) or a combination thereof is thermodynamically stable. Furthermore, the photovoltaic cells according to the invention have high efficiencies of more than 15%, since an intermediate level in the energy level due to the dopants contained in the semiconductor material. bridge of the photovoltaically active semiconductor material is generated. Without an intermediate level, only such photons can lift electrons or charge carriers from the valence band into the conduction band, which have at least the energy of the energy gap. Higher energy photons also contribute to efficiency, with the excess of energy lost to the bandgap as heat. With the intermediate level present in the semiconductor material used for the present invention, which can be partially filled, more photons can contribute to the excitation.
Die erfindungsgemäße photovoltaische Zelle ist vorzugsweise so aufgebaut, dass sie eine p-leitende Absorberschicht aus dem Material der Formel (I), der Formel (II) oder einer Kombination daraus enthält. An diese Absorberschicht aus dem p-leitenden Halbleitermaterial grenzt eine n-leitende, das einfallende Licht möglichst nicht absorbierende Kontaktschicht, vorzugsweise eine n-leitende transparente Schicht, die mindestens ein Halbleitermaterial ausgewählt aus der Gruppe Indium-Zinn-Oxid, fluordotiertes Zinnoxid, antimondotiertes, galliumdotiertes, indiumdotiertes und aluminiumdotiertes Zinkoxid enthält. Einfallendes Licht erzeugt eine positive und eine negative Ladung in der p-leitenden Halbleiterschicht. Die Ladungen diffundieren im p-Gebiet. Nur wenn die negative Ladung die p-n-Grenzschicht erreicht, kann sie das p-Gebiet verlassen. Ein Strom fließt, wenn die negative Ladung den an der Kontaktschicht angebrachten Frontkontakt erreicht hat.The photovoltaic cell of the present invention is preferably constructed to contain a p-type absorber layer of the material of the formula (I), the formula (II) or a combination thereof. Adjacent to this absorber layer of the p-type semiconductor material is an n-conducting contact layer which is as non-absorbent as possible, preferably an n-conducting transparent layer comprising at least one semiconductor material selected from the group consisting of indium tin oxide, fluorine doped tin oxide and antimony doped contains gallium-doped, indium-doped and aluminum-doped zinc oxide. Incident light generates a positive and a negative charge in the p-type semiconductor layer. The charges diffuse in the p-region. Only when the negative charge reaches the p-n interface can it leave the p-region. A current flows when the negative charge has reached the front contact attached to the contact layer.
Gemäß einer bevorzugten Ausführungsform der erfindungsgemäßen photovoltaischen Zelle umfasst diese ein elektrisch leitfähiges Substrat, eine p-Schicht aus dem erfin- dungsgemäßen Halbleitermaterial der Formel (I) und/oder (II) mit einer Dicke von 0,1 bis 20 μm, bevorzugt von 0,1 bis 10 μm, besonders bevorzugt von 0,3 bis 3 μm, und eine n-Schicht aus einem n-leitenden Halbleitermaterial mit einer Dicke von 0,1 bis 20 μm, bevorzugt 0,1 bis 10 μm, besonders bevorzugt 0,3 bis 3 μm. Vorzugsweise ist das Substrat eine mit einem elektrisch leitfähigen Material beschichtete Glasscheibe, eine flexible Metallfolie oder ein flexibles Metallblech. Durch eine Kombination aus einem flexiblen Substrat mit dünnen photovoltaisch aktiven Schichten ergibt sich der Vorteil, dass keine aufwändigen und damit teuren Auflager zur Halterung der die erfindungsgemäßen photovoltaischen Zellen enthaltenden Solarmodule eingesetzt werden müssen. Durch die Flexibilität ist eine Verwindung möglich, so dass sehr einfache und preiswerte Tragekonstruktionen eingesetzt werden können, die nicht verwindungssteif sein müssen. Als bevorzugtes flexibles Substrat wird bei der vorliegenden Erfindung insbesondere ein Edelstahlblech verwendet. Ferner enthält die erfindungsgemäße photovoltaische Zelle vorzugsweise eine Schicht aus Molybdän oder Wolfram mit einer bevorzugten Dicke zwischen 0,1 und 2 μm, die als Barriereschicht und zur Erleichte- rung des Austritts der Elektronen in den Absorber und als Rückkontakt im Fall von Glas als Substrat verwendet wird.According to a preferred embodiment of the photovoltaic cell according to the invention, this comprises an electrically conductive substrate, a p-layer of the inventive semiconductor material of the formula (I) and / or (II) with a thickness of 0.1 to 20 .mu.m, preferably of 0 , 1 to 10 microns, more preferably from 0.3 to 3 microns, and an n-layer of an n-type semiconductor material having a thickness of 0.1 to 20 microns, preferably 0.1 to 10 microns, more preferably 0, 3 to 3 μm. The substrate is preferably a glass pane coated with an electrically conductive material, a flexible metal foil or a flexible metal sheet. By a combination of a flexible substrate with thin photovoltaically active layers, there is the advantage that no expensive and thus expensive supports for holding the solar cells according to the invention containing photovoltaic cells must be used. Due to the flexibility of a twisting is possible, so that very simple and inexpensive support structures can be used, which need not be torsionally stiff. As the preferred flexible substrate, a stainless steel sheet is particularly used in the present invention. Furthermore, the photovoltaic cell according to the invention preferably contains a layer of molybdenum or tungsten having a preferred thickness of between 0.1 and 2 .mu.m, which is used as barrier layer and for facilitating tion of the exit of the electrons in the absorber and is used as the back contact in the case of glass as a substrate.
Die Erfindung bezieht sich weiterhin auf ein Verfahren zur Herstellung des erfindungsgemäßen photovoltaisch aktiven Halbleitermaterials und/oder einer erfindungsgemä- ßen photovoltaischen Zelle umfassend die Schritte:The invention further relates to a method for producing the photovoltaically active semiconductor material according to the invention and / or a photovoltaic cell according to the invention, comprising the steps:
Erzeugen einer Schicht aus einem Halbleitermaterial der Formel Zn1-xMgxTe oderGenerating a layer of a semiconductor material of the formula Zn 1-x Mg x Te or
ZnTe undZnTe and
Einbringen eines Dotiermittels MnTem bzw. MeaMb in die Schicht,Introducing a dopant M n Te m or Me a M b into the layer,
wobei M für mindestens ein Element ausgewählt aus der Gruppe Si, Ge, Sn, Pb, Sb und Bi steht und Me für mindestens ein Element ausgewählt aus der Gruppe Mg und Zn steht, mit x = 0 bis 0,5 y = 0,0001 bis 0,05 n = 1 bis 2 m = 0,5 bis 4 a = 1 bis 5 und b = 1 bis 3.wherein M is at least one element selected from the group Si, Ge, Sn, Pb, Sb and Bi and Me is at least one element selected from the group Mg and Zn, where x = 0 to 0.5 y = 0.0001 to 0.05 n = 1 to 2 m = 0.5 to 4 a = 1 to 5 and b = 1 to 3.
Die aus dem Halbleitermaterial der Formel Zn1-JVIgxTe oder ZnTe erzeugte Schicht weist dabei vorzugsweise eine Dicke von 0,1 bis 20 μm, bevorzugt von 0,1 bis 10 μm, besonders bevorzugt von 0,3 bis 3 μm auf. Diese Schicht wird vorzugsweise durch mindestens ein Abscheidungsverfahren ausgewählt aus der Gruppe Sputtern, elektro- chemisches Abscheiden und stromloses Abscheiden erzeugt. Sputtern bezeichnet das Herausschlagen von Clustern, die etwa 10 bis 10.000 Atome umfassen, aus einem als Elektrode dienenden Sputtertarget durch beschleunigte Ionen und die Deposition des herausgeschlagenen Materials auf einem Substrat. Die gemäß dem erfindungsgemäßen Verfahren hergestellten Schichten aus dem Halbleitermaterial der Formel (I) und/oder (II) werden besonders bevorzugt durch Sputtern hergestellt, weil gesputterte Schichten erhöhte Qualitäten aufweisen. Möglich ist aber auch die Abscheidung von Zink und dem Dotiermetall M und gegebenenfalls Mg auf einem geeigneten Substrat und die nachträgliche Reaktion mit einem Te-Dampf bei Temperaturen unterhalb von 400°C und in Gegenwart von Wasserstoff. Ferner ist auch die elektrochemische Ab- Scheidung von ZnTe zum Erzeugen einer Schicht und das nachträgliche Dotieren dieser Schicht mit einem Dotiermittel zum Erzeugen eines Halbleitermaterials der Formel (I) und/oder (II) geeignet.The layer formed from the semiconductor material of the formula Zn 1-x Te JVIg or ZnTe preferably has a thickness of 0.1 microns to 20, preferably from 0.1 to 10 .mu.m, particularly preferably from 0.3 to 3 microns. This layer is preferably produced by at least one deposition process selected from the group sputtering, electrochemical deposition and electroless deposition. Sputtering refers to the knocking out of clusters comprising about 10 to 10,000 atoms from an electrode sputtering target by accelerated ions and the deposition of the knocked-out material onto a substrate. The layers of the semiconductor material of the formula (I) and / or (II) produced according to the method according to the invention are particularly preferably produced by sputtering because sputtered layers have increased qualities. However, it is also possible to deposit zinc and the doping metal M and optionally Mg on a suitable substrate and to subsequently react with a Te vapor at temperatures below 400 ° C. and in the presence of hydrogen. Furthermore, the electrochemical deposition of ZnTe for producing a layer and the subsequent doping of this layer with a dopant for producing a semiconductor material of the formula (I) and / or (II) are also suitable.
Besonders bevorzugt ist das Einbringen des Dotiermetalls während der Synthese des Zinktellurids in evakuierten Quarzgefäßen. Dabei werden Zink, ggf. Magnesium, Tellur sowie das Dotiermetall oder Mischungen der Dotiermetalle in das Quarzgefäß eingefüllt, das Quarzgefäß evakuiert und im Vakuum abgeschmolzen. Danach wird das Quarzgefäß in einem Ofen erhitzt, zunächst rasch auf ca. 400°C, weil unterhalb der Schmelzpunkte von Zn und Te keine Reaktion stattfindet. Sodann wird die Temperatur langsamer erhöht mit Raten von 20 bis 100°C/h bis auf 800 bis 1200°C, vorzugsweise auf 1000 bis 1100°C. Bei dieser Temperatur findet die Ausbildung des Festkörpergefü- ges statt. Die dazu notwendige Zeit beträgt 1 bis 100 h, bevorzugt 5 bis 50 h. Danach findet das Erkalten statt. Der Inhalt des Quarzgefäßes wird unter Feuchteausschluss auf Teilchengrößen von 0,1 bis 1 mm zerbrochen und diese Teilchen werden dann zum Beispiel in einer Kugelmühle auf Teilchengrößen von 1 bis 30 μm, bevorzugt 2 bis 20 μm verkleinert. Aus dem so erhaltenen Pulver werden durch Heißpressen bei 300 bis 1200°C, bevorzugt bei 400 bis 700°C und Drucken von 5 bis 500 MPa, vorzugsweise bei 20 bis 200 MPa Sputtertargets hergestellt. Die Presszeiten betragen 0,2 bis 10 h, bevorzugt 1 bis 3 h.Particularly preferred is the introduction of the doping metal during the synthesis of the zinc telluride in evacuated quartz vessels. Here, zinc, possibly magnesium, tellurium as well as the doping metal or mixtures of the doping metals filled in the quartz vessel, the quartz vessel evacuated and sealed off in a vacuum. Thereafter, the quartz vessel is heated in an oven, first rapidly to about 400 ° C, because below the melting points of Zn and Te no reaction takes place. Then, the temperature is increased more slowly with rates of 20 to 100 ° C / h up to 800 to 1200 ° C, preferably to 1000 to 1100 ° C. At this temperature the formation of the solid state takes place. The time required for this is 1 to 100 hours, preferably 5 to 50 hours. Then the cooling takes place. The content of the quartz vessel is crushed under moisture exclusion to particle sizes of 0.1 to 1 mm and these particles are then reduced, for example in a ball mill to particle sizes of 1 to 30 microns, preferably 2 to 20 microns. From the powder thus obtained, sputtering targets are prepared by hot pressing at 300 to 1200 ° C, preferably 400 to 700 ° C and pressures of 5 to 500 MPa, preferably 20 to 200 MPa. The pressing times are from 0.2 to 10 h, preferably 1 to 3 h.
Gemäß einer bevorzugten Ausführungsform des erfindungsgemäßen Verfahrens zur Herstellung eines photovoltaisch aktiven Halbleitermaterials und/oder einer photovol- taischen Zelle wird ein Sputtertarget der Formel (Zn1-xMgxTe)i-y(MnTem)y und/oder (ZnTe)i.y(MeaMb)y hergestellt durchAccording to a preferred embodiment of the inventive method for producing a photovoltaically active semiconductor material and / or a photovoltaic cell is a sputtering target of the formula (Zn 1-x Mg x Te) i -y (M n Te m ) y and / or (ZnTe ) i. y (Me a M b ) y produced by
a) Umsetzung von Zn, Te, M und ggf. Mg in evakuierten Quarzröhren bei 800 bis 1200°C, bevorzugt bei 1000 bis 1 1000C, innerhalb von 1 bis 100 h, bevorzugt innerhalb von 5 bis 50 h, zum Erhalt eines Materials, b) Mahlen des Materials nach dem Erkalten unter weitgehendem Ausschluss von Luftsauerstoff und Feuchte zu einem Pulver mit Teilchengrößen von 1 bis 30 μm, bevorzugt von 2 bis 20 μm, und c) Heißpressen des Pulvers bei Temperaturen von 300 bis 1200°C, bevorzugt von 400 bis 700°C, bei Drucken von 5 bis 500 MPa, bevorzugt von 20 bis 200 MPa, bei Presszeiten von 0,2 bis 10 h, bevorzugt von 1 bis 3 h.a) reaction of Zn, Te, M and optionally Mg in evacuated quartz tubes at 800 to 1200 ° C, preferably at 1000 to 1 100 0 C, within 1 to 100 h, preferably within 5 to 50 h, to obtain a B) grinding the material after cooling with substantial exclusion of atmospheric oxygen and moisture to give a powder having particle sizes of 1 to 30 μm, preferably 2 to 20 μm, and c) hot pressing the powder at temperatures of 300 to 1200 ° C, preferably from 400 to 700 ° C, at pressures of 5 to 500 MPa, preferably from 20 to 200 MPa, at press times of 0.2 to 10 h, preferably from 1 to 3 h.
Gemäß einer weiteren Ausführungsform des erfindungsgemäßen Verfahrens zur Herstellung eines photovoltaisch aktiven Halbleitermaterials und/oder einer photovoltai- schen Zelle wird ein Sputtertarget der Formel Zn1-JVIgxTe und/oder ZnTe hergestellt durch a) Umsetzung von Zn, Te und gegebenenfalls Mg in evakuierten Quarzröhren bei 800 bis 1200°C, bevorzugt bei 1000 bis 1100°C, innerhalb von 1 bis 100 h, bevorzugt innerhalb von 5 bis 50 h, zum Erhalt eines Materials, b) Mahlen des Materials nach dem Erkalten unter weitgehendem Ausschluss von Luftsauerstoff und Feuchte zu einem Pulver mit Teilchengrößen von 1 bis 30 μm, bevorzugt von 2 bis 20 μm, und c) Heißpressen des Pulvers bei Temperaturen von 300 bis 1200°C, bevorzugt von 400 bis 700°C, bei Drucken von 5 bis 500 MPa, bevorzugt von 20 bis 200 MPa bei Presszeiten von 0,2 bis 10 h, bevorzugt von 1 bis 3 h.According to a further embodiment of the method according to the invention for producing a photovoltaically active semiconductor material and / or a photovoltaic cell, a sputtering target of the formula Zn 1- JVIg x Te and / or ZnTe is prepared by a) reacting Zn, Te and optionally Mg in evacuated Quartz tubes at 800 to 1200 ° C, preferably at 1000 to 1100 ° C, within 1 to 100 h, preferably within 5 to 50 h, to obtain a material, b) grinding the material after cooling with substantial exclusion of atmospheric oxygen and Moisture to a powder with particle sizes of 1 to 30 .mu.m, preferably from 2 to 20 .mu.m, and c) hot pressing of the powder at temperatures of 300 to 1200 ° C, preferably from 400 to 700 ° C, at pressures of 5 to 500 MPa, preferably from 20 to 200 MPa at press times of 0.2 to 10 h, preferably from 1 to 3 h.
Die Dotiermittel MnTem bzw. MeaMb können nach dem Sputtern in das Zn1-JVIgxTe und/oder ZnTe eingebracht werden. Vorzugsweise wird jedoch das in Schritt a) erhaltene Material in Schritt b) mit dem Dotiermittel MnTem bzw. MeaMb vermählen. Dabei kann ein Teil des Dotiermittels mit dem Zinktellurid in Form einer Reaktionsmahlung abreagieren und in das Wirtsgitter eingebaut werden. Das erfindungsgemäße dotierte Material gemäß Formel (I) oder (II) oder Kombinationen daraus bildet sich dann während des Heißpressens in Schritt c) ausThe dopants M n Te m and Me a M b can be introduced after sputtering in the Zn 1 JVIg x Te and / or ZnTe. Preferably, however, the material obtained in step a) is ground in step b) with the dopant M n Te m or Me a M b . In this case, part of the dopant can react with the zinc telluride in the form of a reaction grinding and be incorporated into the host lattice. The doped material of the formula (I) or (II) or combinations thereof according to the invention then forms during the hot pressing in step c)
In weiteren, dem Fachmann bekannten Verfahrensschritten wird die erfindungsgemäße photovoltaische Zelle durch das erfindungsgemäße Verfahren fertiggestellt.In further process steps known to the person skilled in the art, the photovoltaic cell according to the invention is completed by the method according to the invention.
BeispieleExamples
Die Beispiele wurden nicht an dünnen Schichten, sondern an Pulvern durchgeführt. Die gemessenen Eigenschaften der Halbleitermaterialien mit Dotiermitteln wie Energielü- cke, Leitfähigkeit oder Seebeck-Koeffizient sind nicht dickeabhängig und deshalb genauso aussagekräftig.The examples were not carried out on thin layers, but on powders. The measured properties of the semiconductor materials with dopants such as energy gap, conductivity or Seebeck coefficient are not dependent on thickness and therefore just as meaningful.
Die in der Ergebnistabelle angegebenen Zusammensetzungen wurden in evakuierten Quarzröhren durch Reaktion der Elemente in Gegenwart der Dotiermetalle hergestellt. Dazu wurden die Elemente in einer Reinheit jeweils besser als 99,99 % in Quarzröhren eingewogen, die Restfeuchte durch Erwärmen im Vakuum entfernt und die Röhren im Vakuum abgeschmolzen. In einem schräg stehenden Rohrofen wurden die Röhren innerhalb von 20 h von Raumtemperatur auf 1 100°C erwärmt und die Temperatur sodann 10 h lang bei 1 100°C belassen. Danach wurde der Ofen abgeschaltet und abküh- len gelassen.The compositions given in the result table were prepared in evacuated quartz tubes by reaction of the elements in the presence of the doping metals. For this purpose, the elements were weighed in a purity better than 99.99% in quartz tubes, the residual moisture removed by heating in vacuo and the tubes melted in vacuo. In an inclined tube furnace, the tubes were heated from room temperature to 1 100 ° C within 20 h and the temperature then left at 1100 ° C for 10 h. The oven was then switched off and allowed to cool.
Nach dem Erkalten wurden die so hergestellten Telluride in einem Achatmörser zu Pulver mit Korngrößen unterhalb 30 μm zerkleinert. Dieses Pulver wurde bei Raumtemperatur unter einem Druck von 3000 kp/cm2 zu Scheiben mit 13 mm Durchmesser gepresst.After cooling, the Telluride so prepared were crushed in an agate mortar to powder with particle sizes below 30 microns. This powder was pressed at room temperature under a pressure of 3000 kp / cm 2 to 13 mm diameter disks.
Es wurde jeweils eine Scheibe von grauschwarzer Farbe erhalten, die einen schwachen rötlichen Schimmer aufwies. In einem Seebeck-Experiment wurden die Materialien auf der einen Seite auf 130°C erhitzt, die andere Seite wurde auf 30°C gehalten. Mit einem Voltmeter wurde die Leerlaufspannung gemessen. Dieser Wert dividiert durch 100 ergibt den mittleren in der Ergebnistabelle angegebenen Seebeck-Koeffizienten.In each case a disc of gray-black color was obtained, which had a faint reddish glow. In a Seebeck experiment, the materials were heated on one side to 130 ° C, the other side was kept at 30 ° C. The open circuit voltage was measured with a voltmeter. This value divided by 100 gives the mean Seebeck coefficient given in the result table.
In einem zweiten Experiment wurde die elektrische Leitfähigkeit gemessen. Aus den Absorptionen im optischen Reflexionsspektrum ergaben sich die Werte der Bandlücke zwischen Valenz- und Leitungsband zu 2,2 bis 2,3 eV und jeweils ein Zwischenniveau bei 0,8 bis 1 ,3 eV. In a second experiment, the electrical conductivity was measured. From the absorptions in the optical reflection spectrum, the values of the band gap between valence and conduction band of 2.2 to 2.3 eV and in each case an intermediate level at 0.8 to 1.3 eV.
ErgebnistabelleResults table
Die letzten beiden Zusammensetzungen aus der Ergebnistabelle sind Beispiele für Kombinationen von erfindungsgemäßen Halbleitermaterialien der Formel (I) und der Formel (II) und lassen sich mit der Formel (IM) beschreiben:The last two compositions from the result table are examples of combinations of semiconductor materials according to the invention of the formula (I) and of the formula (II) and can be described by the formula (III):
(Zn1-xMgxTe)i-u-v(MnTem)u(MeaMb)v (III)(Zn 1-x Mg x Te) i -uv (M n Te m ) u (Me a M b ) v (III)
mit u + v = y with u + v = y

Claims

Patentansprüche claims
1. Photovoltaisch aktives Halbleitermaterial der Formel (I), der Formel (II) oder einer Kombination daraus, mit1. Photovoltaically active semiconductor material of the formula (I), the formula (II) or a combination thereof, with
(I) (Zn1-xMgxTe)i-y(MnTem)y und(I) (Zn 1-x Mg x Te) i -y (M n Te m) and y
(II) (ZnTe)i-y(MeaMb)y, wobei(II) (ZnTe) i -y (Me a M b ) y , where
MnTem und MeaMb jeweils ein Dotiermittel ist, in dem M für mindestens ein EIe- ment ausgewählt aus der Gruppe Silizium, Germanium, Zinn, Blei, Antimon undM n Te m and Me a M b are each a dopant in which M for at least one EIe- ment selected from the group silicon, germanium, tin, lead, antimony and
Bismut steht und Me für mindestens ein Element ausgewählt aus der Gruppe Magnesium und Zink steht, mitBismuth stands and Me stands for at least one element selected from the group magnesium and zinc, with
x = 0 bis 0,5 y = 0,0001 bis 0,05 n = 1 bis 2 m = 0,5 bis 4 a = 1 bis 5 und b = 1 bis 3.x = 0 to 0.5 y = 0.0001 to 0.05 n = 1 to 2 m = 0.5 to 4 a = 1 to 5 and b = 1 to 3.
2. Photovoltaische Zelle mit einem photovoltaisch aktiven Halbleitermaterial, wobei das photovoltaisch aktive Halbleitermaterial ein Material der Formel (I), der Formel (II) oder einer Kombination daraus ist, mit2. Photovoltaic cell with a photovoltaically active semiconductor material, wherein the photovoltaically active semiconductor material is a material of the formula (I), the formula (II) or a combination thereof, with
(I) (Zn1-xMgxTe)i-y(MnTem)y und(I) (Zn 1-x Mg x Te) i -y (M n Te m) and y
(II) (ZnTe)i.y(MeaMb)y, wobei(II) (ZnTe) i. y (Me a M b ) y , where
MnTem und MeaMb jeweils ein Dotiermittel ist, in dem M für mindestens ein Element ausgewählt aus der Gruppe Silizium, Germanium, Zinn, Blei, Antimon und Bismut steht und Me für mindestens ein Element ausgewählt aus der GruppeM n Te m and Me a M b are each a dopant in which M is at least one element selected from the group of silicon, germanium, tin, lead, antimony and bismuth and Me is at least one element selected from the group
Magnesium und Zink steht, mitMagnesium and zinc stands, with
x = 0 bis 0,5 y = 0,0001 bis 0,05 n = 1 bis 2 m = 0,5 bis 4 a = 1 bis 5 und b = 1 bis 3. x = 0 to 0.5 y = 0.0001 to 0.05 n = 1 to 2 m = 0.5 to 4 a = 1 to 5 and b = 1 to 3.
3. Photovoltaische Zelle gemäß Anspruch 2, dadurch gekennzeichnet, dass das Dotiermittel mindestens eine Verbindung ausgewählt aus der Gruppe Si3Te3, GeTe, SnTe, PbTe, Sb2Te3, Bi2Te3, Mg2Si Mg2Ge, Mg2Sn, Mg2Pb, Mg3Sb2, Mg3Bi2, ZnSb Zn3Sb2 und Zn4Sb3 ist.3. Photovoltaic cell according to claim 2, characterized in that the dopant at least one compound selected from the group Si 3 Te 3 , GeTe, SnTe, PbTe, Sb 2 Te 3 , Bi 2 Te 3 , Mg 2 Si Mg 2 Ge, Mg 2 Sn, Mg 2 Pb, Mg 3 Sb 2 , Mg 3 Bi 2 , ZnSb Zn 3 Sb 2 and Zn 4 Sb 3 .
4. Photovoltaische Zelle gemäß einem der Ansprüche 2 oder 3, gekennzeichnet durch mindestens eine p-leitende Absorberschicht aus dem Material der Formel (I), der Formel (II) oder einer Kombination daraus.4. Photovoltaic cell according to one of claims 2 or 3, characterized by at least one p-type absorber layer of the material of formula (I), the formula (II) or a combination thereof.
5. Photovoltaische Zelle gemäß einem der Ansprüche 2 bis 4, umfassend eine n- leitende transparente Schicht, die mindestens ein Halbleitermaterial ausgewählt aus der Gruppe Indium-Zinn-Oxid, fluordotiertes Zinnoxid, antimondotiertes Zinkoxid, galliumdotiertes Zinkoxid, indiumdotiertes Zinkoxid und aluminiumdotiertes Zinkoxid enthält.5. A photovoltaic cell according to any one of claims 2 to 4, comprising an n-type transparent layer containing at least one semiconductor material selected from indium-tin oxide, fluorine-doped tin oxide, antimony-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide and aluminum-doped zinc oxide.
6. Photovoltaische Zelle gemäß einem der Ansprüche 2 bis 5, gekennzeichnet durch mindestens eine p-leitende Schicht aus dem Material der Formel (I), der Formel (II) oder einer Kombination daraus, mindestens eine n-leitende Schicht und ein Substrat, wobei das Substrat eine mit einem elektrisch leitfähigen Mate- rial beschichtete Glasscheibe, eine flexible Metallfolie oder ein flexibles Metallblech ist.6. Photovoltaic cell according to one of claims 2 to 5, characterized by at least one p-type layer of the material of formula (I), of formula (II) or a combination thereof, at least one n-type layer and a substrate, wherein the substrate is a glass pane coated with an electrically conductive material, a flexible metal foil or a flexible metal sheet.
7. Verfahren zur Herstellung eines photovoltaisch aktiven Halbleitermaterials gemäß Anspruch 1 oder einer photovoltaischen Zelle gemäß einem der Ansprüche 2 bis 6, gekennzeichnet durch das Erzeugen einer Schicht aus einem Halbleitermaterial der Formel Zn1-JVIgxTe oder ZnTe und Einbringen eines Dotiermittels MnTem bzw. MeaMb in die Schicht.7. A method for producing a photovoltaically active semiconductor material according to claim 1 or a photovoltaic cell according to one of claims 2 to 6, characterized by producing a layer of a semiconductor material of the formula Zn 1- JVIg x Te or ZnTe and introducing a dopant M n Te m or Me a M b in the layer.
8. Verfahren gemäß Anspruch 7, dadurch gekennzeichnet, dass eine Schicht aus dem Halbleitermaterial erzeugt wird, die eine Dicke von 0,1 bis 20 μm aufweist.8. The method according to claim 7, characterized in that a layer of the semiconductor material is produced, which has a thickness of 0.1 to 20 microns.
9. Verfahren gemäß einem der Ansprüche 7 oder 8, dadurch gekennzeichnet, dass die Schicht durch mindestens ein Abscheidungsverfahren ausgewählt aus der Gruppe Sputtern, elektrochemisches Abscheiden und stromloses Abscheiden er- zeugt wird.9. The method according to any one of claims 7 or 8, characterized in that the layer is generated by at least one deposition method selected from the group sputtering, electrochemical deposition and electroless plating.
10. Verfahren gemäß einem der Ansprüche 7 bis 9, gekennzeichnet durch Herstellen eines Sputter-Targets der Formel Zn1-xMgxTe, ZnTe, (Zn1-xMgxTe)i-y(MnTem)y oder (ZnTe)i.y(MeaMb)y durch a) Umsetzung von Zn, Te und gegebenenfalls Mg und M in evakuierten Quarzröhren bei 800 bis 1200°C innerhalb von 1 bis 100 h zum Erhalt eines Materials, b) Mahlen des Materials nach dem Erkalten unter weitgehendem Ausschluss von Luftsauerstoff und Feuchte zu einem Pulver mit Teilchengrößen von 1 bis 30 μm und c) Heißpressen des Pulvers bei Temperaturen von 300 bis 1200°C, bevorzugt von 400 bis 700°C, bei Drucken von 5 bis 500 MPa bei Presszeiten von 0,2 bis 10 h.10. The method according to any one of claims 7 to 9, characterized by preparing a sputtering target of the formula Zn 1-x Mg x Te, ZnTe, (Zn 1-x Mg x Te) i -y (M n Te m ) y or (ZnTe) i. y (Me a M b ) y a) reaction of Zn, Te and optionally Mg and M in evacuated quartz tubes at 800 to 1200 ° C within 1 to 100 h to obtain a material, b) grinding of the material after cooling with substantial exclusion of atmospheric oxygen and moisture to a powder with particle sizes of 1 to 30 microns and c) hot pressing of the powder at temperatures of 300 to 1200 ° C, preferably from 400 to 700 ° C, at pressures of 5 to 500 MPa at press times of 0.2 to 10 h.
1. Verfahren gemäß Anspruch 10, dadurch gekennzeichnet, dass das in Schritt a) durch Umsetzung von Zn, Te und gegebenenfalls Mg erhaltene Material in Schritt b) mit dem Dotiermittel MnTem bzw. MeaMb vermählen wird. 1. Process according to claim 10, characterized in that the material obtained in step a) by reaction of Zn, Te and optionally Mg in step b) is ground with the dopant M n Te m or Me a M b .
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