WO2012054436A1 - Systèmes à énergie solaire en trois dimensions et leurs procédés de réalisation - Google Patents

Systèmes à énergie solaire en trois dimensions et leurs procédés de réalisation Download PDF

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Publication number
WO2012054436A1
WO2012054436A1 PCT/US2011/056647 US2011056647W WO2012054436A1 WO 2012054436 A1 WO2012054436 A1 WO 2012054436A1 US 2011056647 W US2011056647 W US 2011056647W WO 2012054436 A1 WO2012054436 A1 WO 2012054436A1
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Prior art keywords
light
photovoltaic
solar power
power system
openings
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PCT/US2011/056647
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English (en)
Inventor
Mehmet Nadir Dagli
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Solar3D, Inc.
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Priority to CN201180060971.XA priority Critical patent/CN103415929B/zh
Publication of WO2012054436A1 publication Critical patent/WO2012054436A1/fr

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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
    • H01L31/0352—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 shape or by the shapes, relative sizes or disposition of the semiconductor regions
    • H01L31/035272—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 shape or by the shapes, relative sizes or disposition of the semiconductor regions characterised by at least one potential jump barrier or surface barrier
    • H01L31/035281—Shape of the body
    • 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
    • H01L31/0352—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 shape or by the shapes, relative sizes or disposition of the semiconductor regions
    • H01L31/035272—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 shape or by the shapes, relative sizes or disposition of the semiconductor regions characterised by at least one potential jump barrier or surface barrier
    • H01L31/03529—Shape of the potential jump barrier or surface barrier
    • 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
    • H01L31/054—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means
    • H01L31/0543—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means comprising light concentrating means of the refractive type, e.g. lenses
    • 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
    • H01L31/054—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means
    • H01L31/0547—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means comprising light concentrating means of the reflecting type, e.g. parabolic mirrors, concentrators using total internal reflection
    • 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
    • H01L31/054—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means
    • H01L31/056—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means the light-reflecting means being of the back surface reflector [BSR] 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
    • Y02E10/52—PV systems with concentrators

Definitions

  • PV photovoltaic
  • PV systems naturally reflect a significant percentage of incident light (also called “radiation") due to the refractive index difference between the air and the PV cell material.
  • incident light also called “radiation”
  • ohmic contacts and wiring on a surface of conventional PV systems create a shadowing effect, which blocks a fraction of the incident light. Consequently, conventional PV systems are inordinately large and heavy.
  • PV systems typically cover an entire rooftop, reducing the home's visual appeal.
  • PV systems can be used to provide power to vehicles, including aircraft, watercraft, spacecraft, and the like, but their weight and size negatively impact the payload and fuel requirements of such vehicles.
  • a non-planar (i.e., three dimensional) PV system has a greater surface area and therefore greater solar light conversion efficiency than a planar PV system occupying the same footprint.
  • some non-planar PV systems use carbon nanotube towers that reflect incident light onto each other, thereby capturing more of the incident light than a planar PV system.
  • distributing semiconductor material uniformly over carbon nanotubes is difficult.
  • embodiments of the proposed invention relate to high efficiency three dimensional solar power systems and methods of making such systems.
  • a high efficiency three dimensional solar power system includes a light collector and a first photovoltaic diode arranged to receive light from the light collector.
  • the system further includes a second photovoltaic diode in spaced opposition to the first photovoltaic diode to receive a reflected portion of the light received by the first photovoltaic diode.
  • a high efficiency three dimensional solar power system includes a photovoltaic device including a plurality of photovoltaic diodes and first and second ohmic contacts electrically coupled to n-doped and p- doped sides, respectively, of one of the photovoltaic diodes.
  • the system further includes a light collector configured to manipulate a direction of light that would otherwise be incident on one of the first and second ohmic contacts to instead be incident on one of the photovoltaic diodes.
  • a high efficiency three dimensional solar power system includes a semiconductor material and a plurality of openings patterned in the semiconductor material. Each opening has a sidewall that is doped to form a photovoltaic diode with a sidewall of a neighboring one of the openings.
  • a high efficiency three dimensional solar power system in a fourth example embodiment, includes a light collector and a light conducting waveguide arranged to receive light from the light collector and to redirect the received light.
  • the system further includes a photovoltaic diode arranged to receive the redirected light from the light conducting waveguide.
  • a high efficiency multi-junction three dimensional solar power system includes a first semiconductor layer and a second semiconductor layer formed on the first semiconductor layer.
  • the second semiconductor layer has a different bandgap than the first semiconductor layer.
  • the system further includes a plurality of openings patterned in and extending through the second semiconductor layer and into at least a portion of the first semiconductor layer.
  • Each opening has a sidewall that is doped to form: 1) in the first semiconductor layer, a first photovoltaic diode with a sidewall of a neighboring one of the openings; and 2) in the second semiconductor layer, a second photovoltaic diode with the sidewall of the neighboring opening, the second photovoltaic diode having a different bandgap than the first photovoltaic diode.
  • a method of making a high efficiency three dimensional solar power system includes patterning a plurality of openings in a semiconductor material; p-doping sidewalls of a first subset of the openings; n-doping sidewalls of a second, remaining subset of the openings, each of the n-doped openings neighboring one of the p-doped openings to form a photovoltaic diode between each neighboring opening; patterning a plurality of ohmic contacts on the edges of each opening, the ohmic contacts being in an electrically conductive relationship with the doped sidewalls of each opening; filling at least some of the openings with a dielectric material such that an exposed portion of the dielectric material extends over the ohmic contacts, the dielectric material having a lower index of refraction than the semiconductor material; and using the exposed portion of the dielectric material extending over the ohmic contacts to form a plurality of light collectors, each light collector positioned above
  • a method of making a high efficiency three dimensional solar power system includes mounting a first photovoltaic device in spaced opposition to a second photovoltaic device on a printed circuit board; fabricating a light collector having a waveguide into which collected light is directed, the light collector having a lower index of refraction than a material used to form the first and second photovoltaic devices; and securing a position of the light collector such that the waveguide of the light collector occupies a space between the first and second photovoltaic devices to enable absorption of the collected light by the first and second photovoltaic devices.
  • Figure 1 depicts a plan view of an embodiment in which Fresnel lenses are used to collect light
  • Figure 2 depicts a first cross sectional view of the embodiment in Figure 1 ;
  • Figure 3 depicts a second cross sectional view of the embodiment in Figure 1;
  • Figure 4 depicts a plan view of an embodiment in which hemispherical lenses are used to collect light
  • Figure 5 depicts a plan view of an embodiment in which cones are used to collect light
  • Figure 6 depicts a plan view of a multi-junction embodiment of a solar power system in which multiple vertically oriented photovoltaic diodes are made of different semiconductor materials to absorb radiation over a wider spectrum than photovoltaic diodes made of a single semiconductor material;
  • Figure 7 depicts a first perspective view of an embodiment of an example hybrid solar power system in which photovoltaic devices having photovoltaic diodes are fabricated separately from light collectors;
  • Figure 8 depicts a second perspective view of an embodiment of an example hybrid solar power system in which photovoltaic devices having photovoltaic diodes are fabricated separately from light collectors.
  • Figures 9 through 20 depict various views of embodiments of a solar power system in which photovoltaic diodes are oriented horizontally with respect to a substrate.
  • Figure 9 depicts a plan view of an embodiment in which waveguides extending from pairs of light collectors redirect incident light to be absorbed by photovoltaic diodes surrounding the waveguides on all sides;
  • Figure 10 depicts a first cross sectional view of the embodiment in Figure 9;
  • Figure 1 1 depicts a second cross sectional view of the embodiment in Figure
  • Figure 12 depicts a plan view of an embodiment in which the waveguides of
  • Figure 13 depicts a first cross sectional view of the embodiment in Figure 12;
  • Figure 14 depicts a second cross sectional view of the embodiment in Figure
  • Figure 15 depicts a plan view of an embodiment in which the waveguides of the Figure 12 embodiment that redirect incident light are surrounded only on top and bottom sides by photovoltaic diodes;
  • Figure 16 depicts a first cross sectional view of the embodiment in Figure 15;
  • Figure 17 depicts a second cross sectional view of the embodiment in Figure
  • Figure 18 depicts a plan view of an embodiment in which the upper photovoltaic diodes of the Figure 15 embodiment are omitted;
  • Figure 19 depicts a first cross sectional view of the embodiment in Figure 18.
  • Figure 20 depicts a second cross sectional view of the embodiment in Figure
  • Figures 21 through 44 depict various stages of fabrication of the example solar power systems depicted in Figures 1 through 6.
  • Figure 21 depicts a plan view of a first stage of fabrication in which openings are formed in a substrate of semiconductor material, which may contain either a single semiconductor material or a multi junction semiconductor material;
  • Figure 22 depicts a first cross sectional view of the first stage of fabrication depicted in Figure 21 ;
  • Figure 23 depicts a second cross sectional view of the first stage of fabrication depicted in Figure 21 ;
  • Figure 24 depicts a plan view of a second stage of fabrication in which a first diffusion mask is applied over the semiconductor material
  • Figure 25 depicts a first cross sectional view of the second stage of fabrication depicted in Figure 24;
  • Figure 26 depicts a second cross sectional view of the second stage of fabrication depicted in Figure 24;
  • Figure 27 depicts a plan view of a third stage of fabrication in which a plurality of portions of the first diffusion mask of Figure 24 are removed to expose openings that are to be p-doped;
  • Figure 28 depicts a first cross sectional view of the third stage of fabrication depicted in Figure 27
  • Figure 29 depicts a second cross sectional view of the third stage of fabrication depicted in Figure 27;
  • Figure 30 depicts a plan view of a fourth stage of fabrication in which the exposed openings are p-doped, the first diffusion mask is removed, and a second diffusion mask is applied over the semiconductor material;
  • Figure 31 depicts a first cross sectional view of the fourth stage of fabrication depicted in Figure 30;
  • Figure 32 depicts a second cross sectional view of the fourth stage of fabrication depicted in Figure 30;
  • Figure 33 depicts a plan view of a fifth stage of fabrication in which a plurality of portions of the second diffusion mask of Figure 30 are removed to expose openings that are to be n-doped;
  • Figure 34 depicts a first cross sectional view of the fifth stage of fabrication depicted in Figure 33;
  • Figure 35 depicts a second cross sectional view of the fifth stage of fabrication depicted in Figure 33;
  • Figure 36 depicts a plan view of a sixth stage of fabrication in which the second diffusion mask is removed
  • Figure 37 depicts a first cross sectional view of the sixth stage of fabrication depicted in Figure 36;
  • Figure 38 depicts a second cross sectional view of the sixth stage of fabrication depicted in Figure 36;
  • Figure 39 depicts a plan view of a seventh stage of fabrication in which a plurality of ohmic contacts are formed on the edges of each doped opening;
  • Figure 40 depicts a first cross sectional view of the seventh stage of fabrication depicted in Figure 39;
  • Figure 41 depicts a second cross sectional view of the seventh stage of fabrication depicted in Figure 39;
  • Figure 42 depicts a plan view of an eighth stage of fabrication in which the openings are filled with a dielectric material with which light collectors are subsequently formed;
  • Figure 43 depicts a first cross sectional view of the eighth stage of fabrication depicted in Figure 42; and Figure 44 depicts a second cross sectional view of the eighth stage of fabrication depicted in Figure 42.
  • Embodiments of solar power systems and methods of making such systems described herein provide, among other things, increased efficiency of electricity generation relative to footprint size.
  • a unique three dimensional structure implemented in example embodiments increases efficiency by increasing an amount of PV diode surface area exposed to incident radiation relative to a footprint size.
  • the unique three dimensional structure also provides more opportunities for reflected light to be absorbed than conventional three dimensional structures and, in certain embodiments, prevents escape of any incident radiation that is capable of being absorbed by the particular PV diode material used.
  • multiple PV diodes are arranged to absorb radiation over a wider spectrum than one PV diode could absorb.
  • the efficiency of electricity generation per unit footprint area is also increased in certain embodiments due to the relative thinness of PV diodes used to absorb radiation.
  • the present invention can be embodied in various different ways.
  • example embodiments in which PV diodes are arranged in a first orientation are described, followed by a subsection describing example embodiments in which PV diodes are arranged in a second orientation.
  • a third subsection describes an example method of fabricating an example solar power system embodiment.
  • FIGs 1 through 6 depict various embodiments of example solar power systems in which PV diodes are oriented substantially perpendicular to a supporting substrate made of semiconductor material. Hence, the PV diodes are said to be arranged in a "vertical" orientation.
  • Figure 1 depicts a plan view of a solar power system 100
  • Figure 2 depicts a cross sectional view of system 100 taken along section 2-2
  • Figure 3 depicts a cross sectional view of system 100 taken along section 3-3.
  • Solar power system 100 includes a plurality of openings 102 formed in a substrate 104 of semiconductor material and a plurality of P V diodes 106 formed by doping sidewalls of each opening 102.
  • each opening 102 in system 100 has sidewalls that form PV diodes with sidewalls of neighboring openings and each PV diode 106 formed in the sidewalls is in spaced opposition to another PV diode 106.
  • System 100 further includes light collectors 108. Each light collector 108 is positioned over a corresponding one of openings 102.
  • System 100 also includes a first plurality of ohmic contacts 1 10 and a second plurality of ohmic contacts 1 12 positioned on edges of each opening 102 and electrically coupled to n-doped and p- doped sides, respectively, of the plurality of PV diodes 106.
  • Metal interconnections (not shown) connect ohmic contacts 110, 112 of individual PV diodes 106 in series and/or in parallel according to any desired interconnection pattern.
  • Light collectors 108 manipulate a direction of light that would otherwise be incident on first and second plurality of ohmic contacts 110, 112 to instead be incident on PV 106 diodes within openings 102.
  • a dielectric material 1 14 having a low index of refraction such as a polymer (e.g., PolyMethylMethAcrylate (PMMA)), or silicon dioxide, fills openings 102 of system 100 and extends out of openings 102, thereby covering ohmic contacts 110, 112 and ridges between openings 102.
  • PMMA PolyMethylMethAcrylate
  • optical rays such as optical ray 116, enter the portion of dielectric material 114 that fills each opening with an increased angular spread.
  • the optical rays travel through and are absorbed by vertically oriented PV diodes 106 formed in the sidewalls of each opening 102.
  • the optical rays may not be completely absorbed by their initial incidence on a PV diode.
  • a first portion 116-1 of ray 116 may be transmitted through PV diode 106-1 and a second portion 116-2 of ray 116 may be reflected.
  • First partial ray 1 16-1 refracted through PV diode 106-1 may be partially absorbed and partially reflected back into PV diode 106-1 at the interface of PV diode 106-1 with the portion of dielectric material 1 14 that fills the neighboring opening.
  • first partial ray 11 -1 may not be reflected back into PV diode 106-1 , however, and may instead be refracted through the neighboring opening's dielectric material and then refracted through neighboring PV diode 106-2 for absorption and possibly reflected back to PV diode 106-1.
  • the reflection and refraction of rays continues until PV diodes 106 absorb the entire portion of the optical rays' spectrum capable of being absorbed by the particular PV diode material used.
  • second partial ray 1 16-2 is reflected into dielectric material 114 and to another neighboring PV diode 106-3 where it undergoes absorption, reflection, and refraction into a neighboring opening as described above with respect to PV diodes 106-1 and 106-2.
  • PV diodes 106 The multiple reflections both internal and external to PV diodes 106 extend the paths of optical rays entering system 100 beyond what is possible in conventional three dimensional PV structures.
  • the optical paths are extended and increased electricity is generated relative to conventional structures of the same footprint size due to the arrangement of PV diodes 106 and light collectors 108.
  • thin PV diodes are more efficient at converting photons to electric current than thick PV diodes, more light is reflected by and/or transmitted through thin PV diodes than thick PV diodes.
  • this drawback is converted to an advantage in system 100 because light reflections and transmissions relative to one PV diode 106 are received and absorbed by neighboring PV diodes 106 and eventually absorbed. Accordingly, PV diodes 106 in system 100 can be formed as thinly as desired to increase output efficiency.
  • the extended lengths of optical ray paths are also due to the difference in refractive indices of dielectric material 114 and the semiconductor material used to implement PV diodes 106.
  • dielectric material 1 14 has an index of refraction of about 1.5 and the semiconductor material has an index of refraction of about 3.5.
  • the angle of refraction of the light ray entering an absorbing PV diode is about 25°.
  • the angle of refraction is even lower, i.e., ⁇ 2 ⁇ 25" . Therefore light rays incident on the surface of a PV diode on the sidewall of an opening will travel a path that makes an angle of 25° or less with respect to the normal of the sidewall.
  • Light collectors 108 may be implemented in a variety of forms, such as a Fresnel lens, as shown in Figures 1 through 3, or as a hemispherical lens, collecting cone, a zone plate, etc., all of which perform a similar function of collecting and directing light into openings 102.
  • Figure 4 depicts an alternative system 400 in which light collectors 108 are hemispherical lenses.
  • light collectors 108 When light collectors 108 are implemented as lenses, as in systems 100 and 400, light collectors 108 not only collect light but can also manipulate or focus light so as to enter openings 102 with greater angular spread than would otherwise occur.
  • Figure 5 depicts an alternative system 500 in which light collectors 108 are cones.
  • light collectors 108 are implemented as cones, as shown in Figure 5, the cones are angled with respect to a top surface 118 of the semiconductor material to maximize collection of light into openings 102, permitting little or no light to enter air pockets 120 between adjacent collecting cones.
  • FIG. 6 depicts an alternative system 600 in which multi-junction PV diodes 602 are formed in the sidewalls of openings 102.
  • PV diodes 102 are only able to absorb a single portion of the spectrum of optical radiation entering openings 102.
  • This drawback is addressed in system 600 by forming a heterojunction stacked configuration of PV diodes 602 made of different semiconductor materials having different bandgaps.
  • the multi-junction PV diodes 602 of different bandgaps may be stacked such that a widest bandgap PV diode 602-1 is nearest the mouth of each opening 102 and PV diodes 602-2 through 602-n of progressively narrower bandgaps are stacked below PV diode 602-1.
  • multi-junction system 600 of Figure 6 includes all the benefits described above in systems 100, 400 and 500, but also enhances efficiency by absorbing more of the available spectrum.
  • any number of PV diodes 602 may be stacked in system 600.
  • three different semiconductor materials are used to form a stack of PV diodes.
  • a top-most PV diode 602-1 is formed using indium gallium phosphate (In0.sGao.5P) as the semiconductor material
  • second PV diode 602-2 directly under top-most PV diode 602-1 is formed using gallium arsenide (GaAs) as the semiconductor material
  • a third, bottom-most PV diode 602-3 is formed using germanium (Ge) as the semiconductor material.
  • Such a stack of semiconductor materials may be grown monolithically and may be lattice-matched.
  • Openings 102 in each of systems 100 through 600 may be arranged in a repeating row and column pattern, as depicted in Figure 1. However, it will be appreciated that openings 102 are not limited to being arranged in a repeating row and column pattern. For example, openings 102 may simply be arranged in a single row.
  • openings 102 are depicted in Figure 1 as having a square-shaped cross-section as viewed above from a source of light.
  • the length and width of each square-shaped opening is in the range of about 5 microns to about 50 microns— a narrow width on the order of about 1 micron to about 10 microns increases a number of times that light is reflected onto the photosensitive sidewalls relative to a larger opening width.
  • openings 102 are not limited to being square-shaped and may, in fact, be of any cross-sectional shape, including, for example, shapes that can be arranged to form a regular or semiregular tessellation.
  • opening shapes with rectangular cross-sections may be used.
  • a longer side of each rectangle is oriented in-line with the east to west path of the sun when the system is in operation.
  • a depth of openings 102 may vary depending on various factors, such as which semiconductor material is used to form PV diodes 106. For example, if an indirect bandgap semiconductor material, such as silicon, is used, openings of about a 5 micron depth or more may be sufficient to absorb an entire portion of the spectrum that a silicon PV diode is capable of absorbing.
  • each PV diode 106 in systems 100 through 600 is a p-i-n diode and is about 5 microns to about 50 microns thick.
  • the intrinsic, or "i" region, of each PV diode 106 is made thinner than the extrinsically doped "p" and "n" regions.
  • the "i" region may be about 1 micron to about 10 microns thick.
  • a thinner "i" region reduces the likelihood of electron and hole annihilation during light absorption, thereby increasing efficiency of electricity generation.
  • a depth of doping penetration and/or a width of each opening may be varied to control the thickness of the "i" region.
  • Figure 7 depicts a first perspective view and Figure 8 depicts a second perspective view of an example "hybrid" solar power system 700 in which PV devices 706 having PV diodes are fabricated separately from light collectors 708.
  • PV diodes are formed in PV devices 706 according to standard semiconductor processes.
  • the required p-i-n regions of the PV diodes are fabricated as silicon layers over a silicon dioxide layer 715, which is over a silicon substrate 716.
  • Silicon dioxide layers 715 positioned under corresponding the p-i-n regions reflect incident solar radiation, thereby creating multiple reflections of optical rays that traverse the p-i-n regions in the same manner as described in connection with the optical rays in Figures 1 -6 above.
  • PV devices 706 are then mounted on a printed circuit board 709 in a vertical configuration.
  • the fabrication of PV diodes in system 700 does not include formation of openings in the semiconductor material.
  • the PV diodes are arranged in spaced opposition to each other and perpendicular to a supporting substrate, i.e., printed circuit board 709.
  • Each of PV devices 706 includes an n-ohmic contact 710 that is electrically coupled to the n-region of a corresponding PV diode at a first end 711 of PV device 706 and a p-ohmic contact 712 that is electrically coupled to the p-region of the corresponding PV diode at a second end 713 of PV device 706.
  • Ohmic contacts 710 and 712 may also be electrically coupled to contact pads or pins in printed circuit board 709.
  • Light collectors 708 are fabricated with a dielectric material (e.g., PMMA or silicon dioxide) having a lower index of refraction than the semiconductor material used to form the PV diodes. Each of light collectors 708 has or is coupled to a waveguide into which collected light is directed. Since the dielectric material has a lower index of refraction than the semiconductor material, the waveguide permits PV devices 706 to absorb the collected light by refraction. The position of each light collector 708 is secured such that the waveguide occupies a space between two PV devices 706 facing each other in spaced opposition. For example, light collectors 708 may be physically attached to PV devices 706 and/or to printed circuit board 709 using an index matching epoxy.
  • a dielectric material e.g., PMMA or silicon dioxide
  • light collectors 708 are depicted in system 700 as cones, light collectors 708 may instead be formed according to other light collector embodiments featured above in systems 100 through 600. Moreover, light collectors 708 may be sized and configured to accommodate a larger space than exists between pairs of facing PV devices 706 than the corresponding space in systems 100 through 600. Moreover, although Figure 7 depicts n-regions of PV devices 706 as abutting light collectors 708, embodiments are also contemplated in which p-regions abut light collectors 708 or in which a first side of each light collector 708 is abutted by an n-region and a second opposite side is abutted by a p-region.
  • Figures 9 through 20 depict various embodiments of example solar power systems in which a plurality of PV diodes 906 are oriented substantially parallel to a supporting substrate of semiconductor material. Hence, unlike PV diodes 106 in systems 100 through 700, PV diodes 906 of systems in Figures 9 through 20 are said to be arranged in a "horizontal" orientation.
  • the systems of Figures 9 through 20 include many of the same or similar elements as in the systems of Figures 1 through 6, but differ at least in two ways: 1) openings 102 in the semiconductor material are omitted and 2) waveguides and other optional elements that trap and guide radiation to horizontally arranged PV diodes 906 are added.
  • FIG 9 depicts a plan view of a solar power system 900 while Figure 10 depicts a cross sectional view of system 900 taken along section 10-10 and Figure 1 1 depicts a cross sectional view of system 900 taken along section 11-11.
  • Solar power system 900 includes a lower PV diode 906-1 formed according to conventional methods by n-doping and p-doping layers of a semiconductor material, such as silicon or GaAs.
  • a silicon on insulator semiconductor wafer may be used to form this diode.
  • a silicon semiconductor wafer may be oxidized to form a buried silicon dioxide layer 905 over a silicon substrate layer 904.
  • an n-doped layer, an intrinsic layer, and a p-doped layer are formed in the silicon layer over buried silicon dioxide layer 905.
  • System 900 further includes light collectors 908 positioned over lower PV diode 906-1 and a plurality of upper PV diodes 906-2 formed between pairs of light collectors 908.
  • Each light collector 908 is optically coupled to a light conducting waveguide 909.
  • Each light conducting waveguide 909 is arranged to receive light from a corresponding one of light collectors 908 and to redirect the received light. The light is redirected from a substantially vertical direction to a substantially horizontal direction to be received by a portion of lower PV diode 906-1 and a corresponding one of the upper PV diodes 906-2.
  • Part of lower PV diode 906-1 may cover the sidewalls of a horizontal portion of each light conducting waveguide 909 so that the light is completely surrounded by absorbing PV diodes.
  • Light collectors 908 in system 900 are formed with a dielectric material, such as PMMA or silicon dioxide. Moreover, although light collectors 908 are depicted as cones, it will be understood by those of ordinary skill that light collectors 908 may be embodied in various different ways, including, for example, the light collector embodiments shown in Figures 1 and 4.
  • Waveguides 909 in system 900 include horizontal portions 909-1 and vertical portions 909-2. Moreover, waveguides 909 may be integrally formed with the light collectors 908 and may therefore be made with the same dielectric material as light collectors 908.
  • the dielectric material has an index of refraction that is higher than that of air but lower than that of the semiconductor material used to form PV diodes 906. Therefore, collected light is internally reflected by walls of waveguides 909 that interface with air and the collected light is at least partially refracted into PV diodes 906 through the walls of waveguides 909 that interface with PV diodes 906. For example, after being redirected, portions of collected light rays are reflected back and forth between PV diodes 906.
  • each horizontal waveguide portion 909-1 is surrounded on top, bottom, left, and right sides by PV diodes 906. Moreover, each horizontal waveguide portion 909-1 extends between two vertical portions 909-2 and is of a sufficient length that all or almost all of the light is eventually absorbed by PV diodes 906. For example, a length of each horizontal waveguide portion 909-1 may be about 10 microns if an indirect bandgap material, such as silicon, is used to form PV diodes 906.
  • each horizontal waveguide portion 909-1 may need to be only about 1 to about 2 microns for a sufficient number of reflections to occur and the entire portion of the spectrum that GaAs PV diodes are capable of absorbing is absorbed.
  • the light received by light collectors 908 may be redirected by waveguides 909 from a vertical to horizontal direction in various ways.
  • a dielectric or metal mirror 909-3 may be positioned below each vertical waveguide portion 909-2 to reflect light into each horizontal waveguide portion 909-1.
  • each waveguide 909 may include a curved section (not shown) between the vertical and horizontal portions.
  • a first plurality of ohmic contacts 910 are positioned and electrically coupled to n-doped peripheral portions of both lower and upper PV diodes 906-1, 906-2, as shown in Figures 10 and 1 1.
  • a second plurality of ohmic contacts 912 are positioned and electrically coupled to p-doped peripheral portions of both lower and upper PV diodes 906-1, 906-2.
  • Metal interconnections, such as busses 914 connect ohmic contacts 910, 912 of individual PV diodes 906 in series or in parallel according to any desired interconnection pattern.
  • Light collectors 908 and waveguides 909 manipulate a direction of light that would otherwise be incident on ohmic contacts 910, 9 2 to instead be incident on PV diodes 906.
  • System 900 represents only one example embodiment of a horizontal PV diode solar power system. Other example horizontal PV diode embodiments are shown in Figures 12 through 20, described below.
  • Figure 12 depicts a plan view and Figures 13 and 14 depict cross-sectional views of a system 1200 in which each horizontal waveguide portion 909-1 extends from only one corresponding vertical waveguide portion 909-2, as opposed to the configuration in system 900, in which each horizontal waveguide portion 909-1 extends between two vertical waveguide portions 909-2. Consequently, upper PV diodes 906-2 are able to be spaced more closely together in system 1200 than in system 900. Thus, lateral sides of each upper PV diode 906-2 in system 1200 is adjacent to one of the vertical waveguide portions 909-2.
  • system 900 portions of lower PV diode 906-1 that are adjacent to and receive light from horizontal waveguide portions 909-1 are separated by a space between neighboring horizontal waveguide portions 909-1 , whereas in system 1200 of Figures 12 through 14 such spaces are absent.
  • the light intensity in each horizontal waveguide portion 909-1 in system 900 is more uniform than the light intensity in each horizontal waveguide portion 909-1 in system 1200.
  • system 900 uses each horizontal waveguide portion 909-1 more efficiently than system 1200.
  • a further difference in system 1200 with respect to system 900 is the flexibility in layout of ohmic contacts 910, 912 and the busses.
  • busses and ohmic contacts 910, 912 are patterned in elongated straight patterns, as depicted in Figure 12.
  • busses and ohmic contacts 910, 912 may be patterned as they are in system 1200 or, alternatively, ohmic contacts 910, 912 in system 900 may be patterned with less material because ohmic contacts 910, 912 are not needed in the spaces between adjacent pairs of light collectors 908.
  • busses may be patterned in the spaces between adjacent pairs of light collectors 908 in system 900.
  • busses and ohmic contacts 910, 912 can be patterned in a greater variety of ways in system 900 than in system 1200.
  • FIG 15 depicts a plan view and Figures 16 and 17 depict cross-sectional views of an alternative system 1500 in which each horizontal waveguide portion 909- 1 is surrounded only on bottom and top sides by lower and upper PV diodes 906-1 and 906-2, respectively. That is, unlike system 900, each horizontal waveguide portion 909-1 is not embedded in a recession formed in lower PV diode 906-1. Thus, radiation that is incident on the sidewalls of horizontal waveguide portions 909-1 will be reflected back into waveguide portions 909-1 rather than refracted into lower PV diode 906-1 and converted into electricity.
  • each horizontal waveguide portion 909-1 may be elongated with respect to its length in systems 900 and 1200 to provide more opportunities for radiation to be absorbed by the PV diodes.
  • Figure 18 depicts a plan view and Figures 19 and 20 depict cross-sectional views of an alternative system 1800 in which the upper PV diodes 906-2 are omitted and each horizontal waveguide portion 909-1 is adjacent to only lower PV diode 906- 1.
  • System 1800 operates similar to systems 1200 and 1500 discussed above, but is easier to fabricate. Moreover, since absorption of radiation occurs on only one side of each horizontal waveguide portion 909-1, each horizontal waveguide portion 909-1 may be elongated to provide more opportunities for radiation to be absorbed.
  • system 1800 may be modified, if desired, to couple each horizontal waveguide portion 909-1 to two vertical waveguide portions 909-2, as in system 900. Accordingly, a more uniform intensity of light is created in horizontal waveguide portions 909-1 and absorption efficiency is improved.
  • PV diodes 906-1 and 906-2 are implemented as a heterojunction stacked configuration of PV diodes.
  • a heterojunction stacked configuration of PV diodes may be grown monolithically and may be at least partially lattice-matched with different semiconductor materials having different bandgaps.
  • a stack of multiple bandgap PV diodes may be implemented to absorb more of the available spectrum than a PV diode made of a single bandgap material.
  • the different semiconductor materials may be arranged such that a widest bandgap PV diode is nearest a corresponding one of horizontal waveguide portions 909-1.
  • a top-most layer of semiconductor material may be indium gallium phosphate (Ino. 5 Gao. 5 P)
  • a second layer of semiconductor material directly under the top-most layer may be gallium arsenide (GaAs)
  • a third, bottom-most layer of semiconductor material may be germanium (Ge).
  • Figures 21 through 44 graphically show in a progressive format different views of various intermediate states of fabrication of any one of systems 100, 400, 500, and 600 depicted in Figures 1 through 6. An example method of making any one of systems 100, 400, 500, and 600 is explained in detail below with reference to Figures 21 through 44.
  • a plurality of openings or trenches are patterned in a substrate or wafer made of semiconductor material 2100.
  • sidewalls of a first subset of the openings are p-doped, and sidewalls of a second, remaining subset of the openings are n-doped.
  • Each of the n-doped openings neighbors one of the p-doped openings to form a PV diode (corresponding to PV diodes 106) between each neighboring opening.
  • the openings may be doped using semiconductor fabricating processes, such as masking and etching.
  • semiconductor fabricating processes such as masking and etching.
  • a first diffusion mask 2102 is deposited on an exposed surface of semiconductor material 2100, including the inner sidewalls of each opening.
  • First diffusion mask 2102 is then etched away over select openings, as shown in the plan view of Figure 27 and the cross-sectional views of Figures 28 and 29.
  • p-doping is performed by diffusing a p-impurity into the exposed openings to create p-doped sidewalls in the exposed openings
  • the remaining portions of first diffusion mask 2102 are etched away, and a second diffusion mask 2104 is deposited over the exposed surface of the system.
  • Second diffusion mask 2104 is then etched away over the remaining un-doped openings, as shown in the plan view of Figure 33 and the cross- sectional views of Figures 34 and 35.
  • An n-doping process is then performed by diffusing an n-impurity into the exposed openings to create n-doped sidewalls in the exposed openings.
  • the remaining portions of second diffusion mask 2104 are etched away.
  • FIG. 39 and the cross-sectional views of Figures 40 and 41 show an end result of patterning a plurality of ohmic contacts 110, 112 on edges of each opening using semiconductor fabricating processes, such as masking and etching, details of which are omitted for brevity.
  • Ohmic contacts 110, 112 are formed in an electrically conductive relationship with the doped sidewalls of each opening.
  • Appropriate bus wiring (not shown) may also be patterned on the exposed surface of semiconductor material 2100.
  • the openings are filled with dielectric material 114.
  • Dielectric material 114 is selected to have a lower index of refraction than semiconductor material 2100 in which the PV diodes are formed.
  • an exposed portion of dielectric material 114 extends over ohmic contacts 110, 112.
  • light collectors 108 are then formed over corresponding openings to direct light onto the PV diodes (as shown in Figures 1 through 3).
  • the formation of light collectors 108 may vary according to which type of light collector is desired. Thus, Fresnel lenses (system 100 of Figures 1 through 3), hemispherical lenses (system 400 of Figure 4), or collecting cones (system 500 of Figure 5) may be implemented as light collectors 108.

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  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
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  • Computer Hardware Design (AREA)
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  • Photovoltaic Devices (AREA)

Abstract

L'invention porte sur des systèmes à énergie solaire en trois dimensions à haut rendement. Un exemple de système à énergie solaire comprend des collecteurs de lumière et des première et seconde diodes photovoltaïques disposées de façon à recevoir de la lumière à partir du collecteur de lumière. Les diodes photovoltaïques sont en opposition espacée l'une par rapport à l'autre de façon à recevoir des parties de lumière réfléchies l'une de l'autre.
PCT/US2011/056647 2010-10-18 2011-10-18 Systèmes à énergie solaire en trois dimensions et leurs procédés de réalisation WO2012054436A1 (fr)

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CN104659139B (zh) * 2015-02-06 2016-11-23 浙江大学 一种带有菲涅尔透镜纳米结构的太阳能电池

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US6177289B1 (en) * 1998-12-04 2001-01-23 International Business Machines Corporation Lateral trench optical detectors
US7208674B2 (en) * 2001-09-11 2007-04-24 Eric Aylaian Solar cell having photovoltaic cells inclined at acute angle to each other
US20080083963A1 (en) * 2006-10-04 2008-04-10 International Business Machines Corporation P-i-n semiconductor diodes and methods of forming the same
US20090301544A1 (en) * 2008-05-22 2009-12-10 Orbital Sciences Corporation Method of manufacturing flexible, lightweight photovoltaic array
US20100052089A1 (en) * 2008-09-02 2010-03-04 Gady Golan Photoelectric Structure and Method of Manufacturing Thereof
US20100126584A1 (en) * 2008-11-21 2010-05-27 Samsung Electronics Co., Ltd. Solar cells and solar cell modules
US20100132763A1 (en) * 2007-07-06 2010-06-03 Rensselaer Polytechnic Design and fabrication of a local concentrator system

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US6177289B1 (en) * 1998-12-04 2001-01-23 International Business Machines Corporation Lateral trench optical detectors
US7208674B2 (en) * 2001-09-11 2007-04-24 Eric Aylaian Solar cell having photovoltaic cells inclined at acute angle to each other
US20080083963A1 (en) * 2006-10-04 2008-04-10 International Business Machines Corporation P-i-n semiconductor diodes and methods of forming the same
US20100132763A1 (en) * 2007-07-06 2010-06-03 Rensselaer Polytechnic Design and fabrication of a local concentrator system
US20090301544A1 (en) * 2008-05-22 2009-12-10 Orbital Sciences Corporation Method of manufacturing flexible, lightweight photovoltaic array
US20100052089A1 (en) * 2008-09-02 2010-03-04 Gady Golan Photoelectric Structure and Method of Manufacturing Thereof
US20100126584A1 (en) * 2008-11-21 2010-05-27 Samsung Electronics Co., Ltd. Solar cells and solar cell modules

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