Abstract:
A photovoltaic device including a current collection element and a method of making same. The photovoltaic device includes a substrate, a conductive layer, an active photovoltaic material, a transparent electrode and a current collection element. The current collection element includes a transparent support and one or more conductive wires integrated therewith. The conductive wires are in electrical communication with the transparent electrode. Current generated by the active photovoltaic material passes to the transparent electrode. The current collection element facilitates delivery of current passing through the transparent electrode to leads that deliver the current to an external load. The method includes placing a pre-fabricated current collection element in direct contact with the transparent electrode of the photovoltaic device. The time and expense of assembling the conductive wires during fabrication of the photovoltaic device is thereby avoided and higher manufacturing speeds are achieved.
Abstract:
A method and apparatus for forming thin film materials via a plasma deposition process in the presence of a magnetic field. A precursor is delivered to a deposition chamber and activated to form a plasma. The plasma may be initiated in the presence of a magnetic field or subjected to a magnetic field after initiation. The plasma includes ionized and neutral species derived from the precursor and the magnetic field manipulates the plasma to effect a reduction in the population of ionized species and an enhancement of the population of neutral species. A thin film material is subsequently formed from the resulting neutral-enriched deposition medium. The method permits formation of thin film materials having a low density of defects. In one embodiment, the thin film material is a photovoltaic material and the suppression of defects leads to an enhancement in photovoltaic efficiency.
Abstract:
A continuous thin film deposition apparatus that includes a remote plasma source. The source forms a plasma from a precursor and delivers a modified form of the plasma as a charge-depleted deposition medium to a deposition apparatus for formation of a thin film material. The thin film may be formed on a continuous web or other moving substrate. The charge-depleted deposition medium may be formed within the remote plasma source and delivered to an operatively coupled deposition apparatus or the charge-depleted deposition medium may form as the plasma exits the remote plasma source. The initial plasma is formed within the remote plasma source and includes a distribution of charged species (electrons and ions). The charge-depleted deposition medium contains a reduced concentration of the charged species and permits deposition of thin film materials having lower defect concentration. The thin film material may be a solar material.
Abstract:
A method of forming photovoltaic devices and modules that includes an ambient pressure thin film deposition step. The central combination of the photovoltaic device structure includes a back reflector layer, active photovoltaic material and transparent electrode. The central combination is formed on a substrate having an electrical isolation layer deposited thereon. The device structure may further include an overlying protective layer remote from the substrate and a laminate on the backside of the substrate. The individual devices may be interconnected in series via a patterning process to form a monolithically integrated module. Module fabrication is preferably performed in a continuous fashion. One or more steps of module fabrication are performed with a plasma torch. Use of a plasma torch simplifies the manufacturing process by enabling deposition of the electrical isolation and/or protective layers at ambient pressure, including in air.
Abstract:
A photovoltaic device and method of forming a photovoltaic device. The photovoltaic device includes a fluorine-containing photovoltaic material and a transparent electrode. Inclusion of fluorine in the photovoltaic material increases its thermal stability. The effect is particularly pronounced in photovoltaic materials based on disordered forms of silicon, including amorphous, nanocrystalline, or microcrystalline silicon. The higher thermal stability permits deposition or annealing of the transparent electrode at high temperature. As a result, high conductivity is achieved for the transparent electrode without degrading the photovoltaic material. The higher conductivity of the transparent electrode facilitates series integration of individual devices to form a module. The method includes forming a photovoltaic material from a fluorinated precursor or treating a photovoltaic material in a fluorine-containing ambient.
Abstract:
A method that includes forming a photovoltaic material on a substrate and removing the substrate. The method may include patterning the photovoltaic material to form a plurality of photovoltaic devices and configuring the devices in series to achieve monolithic integration. The method may include forming additional layers on the substrate, such as one or more of a protective material, a transparent conductor, a back conductor, an adhesive layer, and a laminate support layer. When the substrate is opaque, the method provides the option of ordering the layers so that a transparent conductor is formed before the back reflector of a photovoltaic stack. This ordering of layers facilitates monolithic integration and the ability to remove the substrate allows the earlier-formed transparent conductor to serve as the point of incidence for receiving the light that excites the photovoltaic material.
Abstract:
A method and apparatus for the high rate deposition of thin film materials on a stationary or continuous substrate. The method includes delivery of a preselected precursor intermediate to a deposition chamber and formation of a thin film material from the intermediate. The intermediate is formed outside of the deposition chamber and includes a metastable species such as a free radical. The intermediate is preselected to include a metastable species conducive to the formation of a thin film material having a low defect concentration. By forming a low defect concentration material, deposition rate is decoupled from material quality and unprecedented deposition rates are achieved. In one embodiment, the preselected precursor intermediate is SiH 3. The method includes combining the preselected intermediate with a carrier gas, preferably in a deactivated state, where the carrier gas directs the transport of the preselected intermediate to a substrate for deposition of the thin film material.
Abstract:
A photovoltaic device structure includes a primer layer to shield the substrate and underlying layers during deposition in an aggressive, highly reactive environment. The primer layer prevents or inhibits etching or other modification of the substrate or underlying layers by highly reactive deposition conditions. The primer layer also reduces contamination of subsequent layers of the device structure by preventing or inhibiting release of elements from the substrate or underlying layers into the deposition environment. The presence of the primer layer extends the range of deposition conditions available for forming photovoltaic or semiconducting materials without compromising performance. The invention allows for the ultrafast formation of silicon-containing amorphous semiconductors from fluorinated precursors in a microwave plasma process. The product materials exhibit high carrier mobility, high photovoltaic conversion efficiency, low porosity, little or no Staebler-Wronski degradation, and low concentrations of electronic and chemical defects.
Abstract:
Apparatus and method for plasma deposition of thin film photovoltaic materials at microwave frequencies. The apparatus avoids unintended deposition on microwave transmission elements that couple microwave energy to deposition species. The apparatus includes a microwave applicator with conduits passing therethrough that carry deposition species. The applicator transfers microwave energy to the deposition species to energize them to a reactive state conducive to formation of a thin film. The conduits physically isolate deposition species that would react or otherwise combine to form a thin film material at the point of microwave power transfer. The deposition species are separately energized and swept away from the point of power transfer to prevent premature thin film deposition. Suitable precursors include those that contain silicon, germanium, fluorine, and/or hydrogen. The invention enables formation of silicon-containing amorphous semiconductors that exhibit high mobility, low porosity, little Staebler-Wronski degradation, and low defect concentration.
Abstract:
A continuous thin film deposition apparatus that includes a remote plasma source. The source forms a plasma from a precursor and delivers a modified form of the plasma as a charge-depleted deposition medium to a deposition apparatus for formation of a thin film material. The thin film may be formed on a continuous web or other moving substrate. The charge-depleted deposition medium may be formed within the remote plasma source and delivered to an operatively coupled deposition apparatus or the charge-depleted deposition medium may form as the plasma exits the remote plasma source. The initial plasma is formed within the remote plasma source and includes a distribution of charged species (electrons and ions). The charge-depleted deposition medium contains a reduced concentration of the charged species and permits deposition of thin film materials having lower defect concentration. The thin film material may be a solar material.