Alliance for Sustainable Energy, LLC

Midwest Research Institute

First Solar, Inc.

Bowling Green State University

Abengoa Solar New Technologies, S.a.

David Scott Albin

Rommel Noufi

James Michael Burst

Joel Nathan Duenow

Miguel A Contreras

John R Tuttle

Wyatt Keith Metzger

Eric Michael Colegrove

James Neil Johnson

Matthew O Reese

Jeffrey J Carapella

Andrew L Tennant

Andrew M Gabor

Scott Daniel Feldman-Peabody

Bastiaan Arie Korevaar

Mark Jeffrey Pavol

Robert Dwayne Gossman

Timothy A Gessert

Yu Zhao

Teresa M Barnes

Marco Nardone

Sebastian Caparros Jimenez

Ramesh G Dhere

Gregory Frank Pach

Joaquin Murillo Gutierrez

Emilio Sanchez Cortezon

Manuel Romero

Helio R Moutinho

Stuart Farrell

Nirav Vora

Disclosed herein are compositions and methods for making polycrystalline thin films having very large grains sizes and exhibiting improved properties over existing thin films.

Extreme large grain (1 mm) lateral growth of Cd(Se,Te) alloy thin films by reactive anneals

Disclosed herein are CdSeTe photovoltaic devices having interdigitated back contact architecture for use in polycrystalline thin films in photovoltaic devices.

CdSeTe photovoltaic devices with interdigitated back contact architecture

Methods for growing and using large-grain templates are provided. According to an aspect of the invention, a method includes depositing a small-grain layer of a semiconductor material; treating the small-grain layer such that the small-grain layer becomes a large-grain layer; and growing an epitaxial layer of the semiconductor material on the large-grain layer. A ratio of an average grain size of the small-grain layer to a thickness of the small-grain layer is less than 1.0, and a ratio of an average grain size of the large-grain layer to a thickness of the large-grain layer is greater than 1.5.

Fabrication and use of large-grain templates for epitaxial deposition of semiconductor materials

Systems and methods for growing high-quality CdTe-based materials at high growth rates are provided. According to an aspect of the invention, a method includes depositing a first CdTe-based layer on a CdTe-based template at a rate of greater than 1 &#x3bc;m/min. Each of the first CdTe-based layer and the CdTe-based template has a single-crystal structure and/or a large-grain polycrystalline structure. The depositing is performed by physical vapor deposition.

Methods of growing CdTe-based materials at high rates

Systems and methods for forming solar cells with CuInSeand Cu(In,Ga)Sefilms are provided. In one embodiment, a method comprises: during a first stage (), performing a mass transport through vapor transport of an indium chloride (InCl) vapor () and Se vapor () to deposit a semiconductor film () upon a substrate (); heating the substrate () and the semiconductor film to a desired temperature (); during a second stage () following the first stage (), performing a mass transport through vapor transport of a copper chloride (CuCl) vapor () and Se vapor () to the semiconductor film (); and during a third stage () following the second stage (), performing a mass transport through vapor transport of an indium chloride (InCl) vapor () and Se vapor () to the semiconductor film ().

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Methods for treating a semiconductor material are provided. According to an aspect of the invention, the method includes annealing the semiconductor material in the presence of a compound that includes a first element and a second element. The first element provides an overpressure to achieve a desired stoichiometry of the semiconductor material, and the second element provides a dopant to the semiconductor material.

Controlling the stoichiometry and doping of semiconductor materials

A method for forming thin films or layers of cadmium telluride (CdTe) for use in photovoltaic modules or solar cells. The method includes varying the substrate temperature during the growth of the CdTe layer by preheating a substrate (e.g., a substrate with a cadmium sulfide (CdS) heterojunction or layer) suspended over a CdTe source to remove moisture to a relatively low preheat temperature. Then, the method includes directly heating only the CdTe source, which in turn indirectly heats the substrate upon which the CdTe is deposited. The method improves the resulting CdTe solar cell reliability. The resulting microstructure exhibits a distinct grain size distribution such that the initial region is composed of smaller grains than the bulk region portion of the deposited CdTe. Resulting devices exhibit a behavior suggesting a more n-like CdTe material near the CdS heterojunction than devices grown with substrate temperatures held constant during CdTe deposition.

Varying cadmium telluride growth temperature during deposition to increase solar cell reliability

A method of producing polycrystalline CdTe materials and devices that incorporate the polycrystalline CdTe materials are provided. In particular, a method of producing polycrystalline p-doped CdTe thin films for use in CdTe solar cells in which the CdTe thin films possess enhanced acceptor densities and minority carrier lifetimes, resulting in enhanced efficiency of the solar cells containing the CdTe material are provided.

CdTe devices and method of manufacturing same

Systems and methods for solar cells with CIS and CIGS films made by reacting evaporated copper chlorides with selenium are provided. In one embodiment, a method for fabricating a thin film device comprises: providing a semiconductor film comprising indium (In) and selenium (Se) upon a substrate; heating the substrate and the semiconductor film to a desired temperature; and performing a mass transport through vapor transport of a copper chloride vapor and se vapor to the semiconductor film within a reaction chamber.

Systems and methods for solar cells with CIS and CIGS films made by reacting evaporated copper chlorides with selenium

A method for making a photovoltaic device is presented. The method includes steps of disposing a window layer on a substrate and disposing an absorber layer on the window layer. Disposing the window layer, the absorber layer, or both layers includes introducing a source material into a deposition zone, wherein the source material comprises oxygen and a constituent of the window layer, of the absorber layer or of both layers. The method further includes step of depositing a film that comprises the constituent and oxygen.

Method for making photovoltaic devices using oxygenated semiconductor thin film layers

A process for producing a slightly Cu-poor thin film of Cu(In,Ga)(Se,S).sub.2 comprises depositing a first layer of (In,Ga).sub.x (Se,S).sub.y followed by depositing just enough Cu+(Se,S) or Cu.sub.x (Se,S) to produce the desired slightly Cu-poor material. In a variation, most, but not all, (about 90 to 99%) of the (In,Ga).sub.x (Se,S).sub.y is deposited first, followed by deposition of all the Cu+(Se,S) or Cu.sub.x (Se,S) to go near stoichiometric, possibly or even preferably slightly Cu-rich, and then in turn followed by deposition of the remainder (about 1 to 10%) of the (In,Ga).sub.x (Se,S).sub.y to end with a slightly Cu-poor composition. In yet another variation, a small portion (about 1 to 10%) of the (In,Ga).sub.x (Se,S).sub.y is first deposited as a seed layer, followed by deposition of all of the Cu+(Se,S) or Cu.sub.x (Se,S) to make a very Cu-rich mixture, and then followed deposition of the remainder of the (In,Ga).sub.x (Se,S).sub.y to go slightly Cu-poor in the final Cu(In,Ga)(Se,S).sub.2 thin film.

Method of fabricating high-efficiency Cu(In,Ga)(SeS).sub.2 thin films

A process for fabricating slightly Cu-poor thin-films of Cu(In,Ga)Se.sub.2 on a substrate for semiconductor device applications includes the steps of forming initially a slightly Cu-rich, phase separated, mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se on the substrate in solid form followed by exposure of the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture to an overpressure of Se vapor and (In,Ga) vapor for deposition on the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture while simultaneously increasing the temperature of the solid mixture toward a recrystallization temperature (about 550.degree. C.) at which Cu(In,Ga)Se.sub.2 is solid and Cu.sub.x Se is liquid. The (In,Ga) flux is terminated while the Se overpressure flux and the recrystallization temperature are maintained to recrystallize the Cu.sub.x Se with the (In, Ga) that was deposited during the temperature transition and with the Se vapor to form the thin-film of slightly Cu-poor Cu.sub.x (In,Ga).sub.y Se.sub.z. The initial Cu-rich, phase separated large grain mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se can be made by sequentially depositing or co-depositing the metal precursors, Cu and (In, Ga), on the substrate at room temperature, ramping up the thin-film temperature in the presence of Se overpressure to a moderate anneal temperature (about 450.degree. C.) and holding that temperature and the Se overpressure for an annealing period. A nonselenizing, low temperature anneal at about 100.degree. C. can also be used to homogenize the precursors on the substrates before the selenizing, moderate temperature anneal.

Recrystallization method to selenization of thin-film Cu(In,Ga)Se.sub.2

Enhanced quality thin films of Cu.sub.w (In,Ga.sub.y)Se.sub.z for semiconductor device applications are fabricated by initially forming a Cu-rich, phase-separated compound mixture comprising Cu(In,Ga):Cu.sub.x Se on a substrate to form a large-grain precursor and then converting the excess Cu.sub.x Se to Cu(In,Ga)Se.sub.2 by exposing it to an activity of In and/or Ga, either in vapor In and/or Ga form or in solid (In,Ga).sub.y Se.sub.z. Alternatively, the conversion can be made by sequential deposition of In and/or Ga and Se onto the phase-separated precursor. The conversion process is preferably performed in the temperature range of about 300.degree.-600.degree. C., where the Cu(In,Ga)Se.sub.2 remains solid, while the excess Cu.sub.x Se is in a liquid flux. The characteristic of the resulting Cu.sub.w (In,Ga).sub.y Se.sub.z can be controlled by the temperature. Higher temperatures, such as 500.degree.-600.degree. C., result in a nearly stoichiometric Cu(In,Ga)Se.sub.2, whereas lower temperatures, such as 300.degree.-400.degree. C., result in a more Cu-poor compound, such as the Cu.sub.z (In,Ga).sub.4 Se.sub.7 phase.

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Denver, CO, United States of America

David Scott Albin