Midwest Research Institute

The United States of America As Represented by the United States

The United States of America As Represented by the Department of Energy

Sol Voltaics Ab

Jerry M Olson

Sarah R Kurtz

Daniel Joseph Friedman

Andrew Gordon Norman

Karen L Carleton

A multi junction photovoltaic cell for converting light into electrical energy, comprising a substrate () having a surface (), wherein a region () at the surface () of the substrate () is doped such that a first p-n junction is formed in the substrate (). The photovoltaic cell has a nanowire () that is arranged on the surface () of the substrate () at a position where the doped region () is located in the substrate (), such that a second p-n junction is formed at the nanowire () and in series connection with the first p-n junction.

Multi-junction photovoltaic cell with nanowires

Nanostructures () and methods for production thereof by phase separation during metal organic vapor-phase epitaxy (MOVPE). An embodiment of one of the methods may comprise providing a growth surface in a reaction chamber and introducing a first mixture of precursor materials into the reaction chamber to form a buffer layer () thereon. A second mixture of precursor materials may be provided into the reaction chamber to form an active region () on the buffer layer (), wherein the nanostructure () is embedded in a matrix () in the active region (). Additional steps are also disclosed for preparing the nanostructure () product for various applications.

[object Object]

A multi-junction, monolithic, photovoltaic solar cell device is provided for converting solar radiation to photocurrent and photovoltage with improved efficiency. The solar cell device comprises a plurality of semiconductor cells, i.e., active p/n junctions, connected in tandem and deposited on a substrate fabricated from GaAs or Ge. To increase efficiency, each semiconductor cell is fabricated from a crystalline material with a lattice constant substantially equivalent to the lattice constant of the substrate material. Additionally, the semiconductor cells are selected with appropriate band gaps to efficiently create photovoltage from a larger portion of the solar spectrum. In this regard, one semiconductor cell in each embodiment of the solar cell device has a band gap between that of Ge and GaAs. To achieve desired band gaps and lattice constants, the semiconductor cells may be fabricated from a number of materials including Ge, GaInP, GaAs, GaInAsP, GaInAsN, GaAsGe, BGaInAs, (GaAs)Ge, CuInSSe, CuAsSSe, and GaInAsNP. To further increase efficiency, the thickness of each semiconductor cell is controlled to match the photocurrent generated in each cell. To facilitate photocurrent flow, a plurality of tunnel junctions of low-resistivity material are included between each adjacent semiconductor cell. The conductivity or direction of photocurrent in the solar cell device may be selected by controlling the specific p-type or n-type characteristics for each active junction.

Multi-junction, monolithic solar cell using low-band-gap materials lattice matched to GaAs or Ge

A high-efficiency single heterojunction solar cell wherein a thin emitter layer (preferably Ga.sub.0.52 In.sub.0.48 P) forms a heterojunction with a GaAs absorber layer. The conversion effiency of the solar cell is at least 25.7%. The solar cell preferably includes a passivating layer between the substrate and the absorber layer. An anti-reflection coating is preferably disposed over the emitter layer.

Heterojunction solar cell

A high-efficiency heterojunction solar cell wherein a thin emitter layer (preferably Ga.sub.0.52 In.sub.0.48 P) forms a heterojunction with a GaAs absorber layer. A passivating window layer of defined composition is disposed over the emitter layer. The conversion efficiency of the solar cell is at least 25.7%. The solar cell preferably includes a passivating layer between the substrate and the absorber layer. An anti-reflection coating is preferably disposed over the window layer.

Heterojunction solar cell with passivated emitter surface

The efficiency of a two-junction (cascade) tandem photovoltaic device is improved by adjusting (decreasing) the top cell thickness to achieve current matching. An example of the invention was fabricated out of Ga.sub.0.52 In.sub.0.48 P and GaAs. Additional lattice-matched systems to which the invention pertains include Al.sub.x Ga.sub.1-x /GaAS (x= 0.3-0.4), GaAs/Ge and Ga.sub.y In.sub.l-y P/Ga.sub.y+0.5 In.sub.0.5-y As (0&lt;y&lt;5).

Current-matched high-efficiency, multijunction monolithic solar cells

A multiple wavelength LED having a monolithic cascade cell structure comprising at least two p-n junctions, wherein each of said at least two p-n junctions have substantially different band gaps, and electrical connector means by which said at least two p-n junctions may be collectively energized; and wherein said diode comprises a tunnel junction or interconnect.

Tunnel junction multiple wavelength light-emitting diodes

A multijunction (cascade) tandem photovoltaic solar cell device is fabricated of a Ga.sub.x In.sub.1-x P (0.505.ltoreq.X.ltoreq.0.515) top cell semiconductor lattice matched to a GaAs bottom cell semiconductor at a low-resistance heterojunction, preferably a p+/n+ heterojunction between the cells. The top and bottom cells are both lattice matched and current matched for high efficiency solar radiation conversion to electrical energy.

Current and lattice matched tandem solar cell

A method for producing high purity silicon includes forming a copper silie alloy and positioning the alloy within an enclosure. A filament member is also placed within the enclosure opposite the alloy. The enclosure is then filled with a chemical vapor transport gas adapted for transporting silicon. Finally, both the filament member and the alloy are heated to temperatures sufficient to cause the gas to react with silicon at the alloy surface and deposit the reacted silicon on the filament member. In addition, an apparatus for carrying out this method is also disclosed.

Method and apparatus for producing high purity silicon

A process for producing silicon includes forming an alloy of copper and silicon and positioning the alloy in a dried, molten salt electrolyte to form a solid anode structure therein. An electrically conductive cathode is placed in the electrolyte for plating silicon thereon. The electrolyte is then purified to remove dissolved oxides. Finally, an electrical potential is applied between the anode and cathode in an amount sufficient to form substantially pure silicon on the cathode in the form of substantially dense, coherent deposits.

Growing community of inventors

Lakewood, CO, United States of America

Jerry M Olson