Alliance for Sustainable Energy, LLC

Midwest Research Institute

University of Colorado

Government of the United States of America, As Represented by the Secretary of Commerce

Howard M Branz

Qi Wang

Hao-Chih Yuan

Pauls Stradins

Charles Teplin

Matthew Robert Page

James Scott Ward

Harold R McHugh

Jihun Oh

David K Benson

C Edwin Tracy

David Samuel Ginley

Mahmoud I Hussein

Kristine A Bertness

Daniel L Meier

Richard S Crandall

Joel Calvin Weber

Vernon Yost

Jian Hu

Anna Duda

Paul Stradins

Fatima Toor

A nanophononic metamaterial-based thermoelectric energy conversion device and processes for fabricating a nanophononic metamaterial-based thermoelectric energy conversion device is provided. In one implementation, for example, a nanophononic metamaterial-based thermoelectric energy conversion device includes a first conductive pad, a second conductive pad, and a plurality of strip units. In one implementation, the first conductive pad is coupled to a first connection of the thermoelectric energy conversion device, and the second conductive pad is coupled to a second connection of the thermoelectric energy conversion device. The plurality of strip units are connected in series between the first and second conductive pads and provide a parallel heat transfer pathway. The strip units include a nanostructure design comprising a nanophononic metamaterial.

Thermoelectric devices based on nanophononic metamaterials

A photovoltaic (PV) device with improved blue response. The PV device includes a silicon substrate with an emitter layer on a light receiving side. The emitter layer has a low opant level such that it has sheet resistance of 90 to 170 ohm/sq. Anti-reflection in the PV device is provided solely by a nano-structured or black silicon surface on the light-receiving surface, through which the emitter is formed by diffusion. The nano structures of the black silicon are formed in a manner that does not result in gold or another high-recombination metal being left in the black silicon such as with metal-assisted etching using silver. The black silicon is further processed to widen these pores so as to provide larger nanostructures with lateral dimensions in the range of 65 to 150 nanometers so as to reduce surface area and also to etch away a highly doped portion of the emitter.

Efficient black silicon photovoltaic devices with enhanced blue response

A method () is provided for processing a graded-density AR silicon surface () to provide effective surface passivation. The method () includes positioning a substrate or wafer () with a silicon surface () in a reaction or processing chamber (). The silicon surface () has been processed () to be an AR surface with a density gradient or region of black silicon. The method () continues with heating () the chamber () to a high temperature for both doping and surface passivation. The method () includes forming (), with a dopant-containing precursor in contact with the silicon surface () of the substrate (), an emitter junction () proximate to the silicon surface () by doping the substrate (). The method () further includes, while the chamber is maintained at the high or raised temperature, forming () a passivation layer () on the graded-density silicon anti-reflection surface ().

Forming high-efficiency silicon solar cells using density-graded anti-reflection surfaces

An apparatus () for detecting slow or thermal neutrons (). The apparatus () includes an alpha particle-detecting layer () that is a hydrogenated amorphous silicon p-i-n diode structure. The apparatus includes a bottom metal contact () and a top metal contact () with the diode structure () positioned between the two contacts () to facilitate detection of alpha particles (). The apparatus () includes a neutron conversion layer () formed of a material containing boron-10 isotopes. The top contact () is pixilated with each contact pixel extending to or proximate to an edge of the apparatus to facilitate electrical contacting. The contact pixels have elongated bodies to allow them to extend across the apparatus surface () with each pixel having a small surface area to match capacitance based upon a current spike detecting circuit or amplifier connected to each pixel. The neutron conversion layer () may be deposited on the contact pixels () such as with use of inkjet printing of nanoparticle ink.

High sensitivity, solid state neutron detector

Methods of preparing a thin crystalline silicon film for transfer and devices utilizing a transferred crystalline silicon film are disclosed. The methods include preparing a silicon growth substrate which has an interface defining substance associated with an exterior surface. The methods further include depositing an epitaxial layer of silicon on the silicon growth substrate at the surface and separating the epitaxial layer from the substrate substantially along the plane or other surface defined by the interface defining substance. The epitaxial layer may be utilized as a thin film of crystalline silicon in any type of semiconductor device which requires a crystalline silicon layer. In use, the epitaxial transfer layer may be associated with a secondary substrate.

Epitaxial growth of silicon for layer transfer

Forming high efficiency silicon solar cells using density-graded anti-reflection surfaces

A method () for etching a silicon surface () to reduce reflectivity. The method () includes electroless deposition of copper nanoparticles about 20 nanometers in size on the silicon surface (), with a particle-to-particle spacing of 3 to 8 nanometers. The method () includes positioning () the substrate () with a silicon surface () into a vessel (). The vessel () is filled () with a volume of an etching solution () so as to cover the silicon surface (). The etching solution () includes an oxidant-etchant solution (), e.g., an aqueous solution of hydrofluoric acid and hydrogen peroxide. The silicon surface () is etched () by agitating the etching solution () with, for example, ultrasonic agitation, and the etching may include heating () the etching solution () and directing light () onto the silicon surface (). During the etching, copper nanoparticles enhance or drive the etching process.

Copper-assisted, anti-reflection etching of silicon surfaces

Exemplary embodiments are disclosed of anti-reflective nanoporous silicon for efficient hydrogen production by photoelectrolysis of water. A nanoporous black Si is disclosed as an efficient photocathode for Hproduction from water splitting half-reaction.

Anti-reflective nanoporous silicon for efficient hydrogen production

An apparatus () for detecting slow or thermal neutrons () including an alpha particle-detecting layer () that is a hydrogenated amorphous silicon p-i-n diode structure. The apparatus includes a bottom metal contact () and a top metal contact () with the diode structure () positioned between the two contacts () to facilitate detection of alpha particles (). The apparatus () includes a neutron conversion layer () formed of a material containing boron-10 isotopes. The top contact () is pixilated with each contact pixel extending to or proximate to an edge of the apparatus to facilitate electrical contacting. The contact pixels have elongated bodies to allow them to extend across the apparatus surface () with each pixel having a small surface area to match capacitance based upon a current spike detecting circuit or amplifier connected to each pixel. The neutron conversion layer () may be deposited on the contact pixels () such as with use of inkjet printing of nanoparticle ink.

A crystal oriented metal back contact for solar cells is disclosed herein. In one embodiment, a photovoltaic device and methods for making the photovoltaic device are disclosed. The photovoltaic device includes a metal substrate with a crystalline orientation and a heteroepitaxial crystal silicon layer having the same crystal orientation of the metal substrate. A heteroepitaxial buffer layer having the crystal orientation of the metal substrate is positioned between the substrate and the crystal silicon layer to reduce diffusion of metal from the metal foil into the crystal silicon layer and provide chemical compatibility with the heteroepitaxial crystal silicon layer. Additionally, the buffer layer includes one or more electrically conductive pathways to electrically couple the crystal silicon layer and the metal substrate.

Back contact to film silicon on metal for photovoltaic cells

A device () comprises a semiconductor diode () and a switchable element () positioned in stacked adjacent relationship. The semiconductor diode () and the switchable element () are electrically connected in series with one another. The switchable element () is switchable from a low-conductance state to a high-conductance state in response to the application of a low-density forming current and/or a low voltage.

Stacked switchable element and diode combination with a low breakdown switchable element

A method () of texturing silicon surfaces () such to reduce reflectivity of a silicon wafer () for use in solar cells. The method () includes filling () a vessel () with a volume of an etching solution () so as to cover the silicon surface) of a wafer or substrate (). The etching solution () is made up of a catalytic nanomaterial () and an oxidant-etchant solution (). The catalytic nanomaterial () may include gold or silver nanoparticles or noble metal nanoparticles, each of which may be a colloidal solution. The oxidant-etchant solution () includes an etching agent (), such as hydrofluoric acid, and an oxidizing agent (), such as hydrogen peroxide. Etching () is performed for a period of time including agitating or stirring the etching solution (). The etch time may be selected such that the etched silicon surface () has a reflectivity of less than about 15 percent such as 1 to 10 percent in a 350 to 1000 nanometer wavelength range.

Nanoparticle-based etching of silicon surfaces

A method of producing epitaxial silicon films on a c-Si wafer substrate using hot wire chemical vapor deposition by controlling the rate of silicon deposition in a temperature range that spans the transition from a monohydride to a hydrogen free silicon surface in a vacuum, to obtain phase-pure epitaxial silicon film of increased thickness is disclosed. The method includes placing a c-Si substrate in a HWCVD reactor chamber. The method also includes supplying a gas containing silicon at a sufficient rate into the reaction chamber to interact with the substrate to deposit a layer containing silicon thereon at a predefined growth rate to obtain phase-pure epitaxial silicon film of increased thickness.

Method for rapid, controllable growth and thickness, of epitaxial silicon films

A device () comprises a semiconductor diode () and a switchable element () positioned in stacked adjacent relationship so that the semiconductor diode () and the switchable element () are electrically connected in series with one another. The switchable element () is switchable from a low-conductance state to a high-conductance state in response to the application of a forming voltage to the switchable element ().

Stacked switchable element and diode combination

A method of producing a metastable degradation resistant amorphous hydrogenated silicon film is provided, which comprises the steps of growing a hydrogenated amorphous silicon film, the film having an exposed surface, illuminating the surface using an essentially blue or ultraviolet light to form high densities of a light induced defect near the surface, and etching the surface to remove the defect.

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Boulder, CO, United States of America

Howard M Branz