Abstract: Embodiments of the inventions provide methods and apparatus to electroplate films of tellurides such as CdTe, or its alloys on multiple large area workpieces. In one embodiment a method of forming a solar cell absorber film on multiple work pieces uses a self adjusting mechanism taking advantage of the high resistivity of the solar cell absorber film. Larger deposits of the plating material onto one workpiece, due for example, to non-uniformity of solution flow, results in larger resistance thus decreasing the current flowing through that workpiece. The decreased current then deposits less material over that workpiece. In another embodiment multiple workpieces can be electroplated using a single power supply in a single plating bath.

Abstract: An electrochemical deposition method to form uniform and continuous Group IIIA material rich thin films with repeatability is provided. Such thin films are used in fabrication of semiconductor and electronic devices such as thin film solar cells. In one embodiment, the Group IIIA material rich thin film is deposited on an interlayer that includes 20-90 molar percent of at least one of In and Ga and at least 10 molar percent of an additive material including one of Cu, Se, Te, Ag and S. The thickness of the interlayer is adapted to be less than or equal to about 20% of the thickness of the Group IIIA material rich thin film.

Abstract: A method of forming metallic connector patterns for solar cells, whereby an embosser having raised features shaped in the form of a metallic connector pattern is used to attach a portion of a metallic foil to a transparent conductive layer formed on a top transparent surface of a solar cell structure. The raised surfaces of the embosser press the metallic foil portion against the transparent conductive layer. Heat and pressure directed to the metallic foil portion attach the metallic foil portion to the underlying transparent conductive layer, and then the rest of the metallic foil, which is not attached to the transparent conductive layer, is removed.

Abstract: An electrochemical co-deposition method and solution to plate uniform, defect free and smooth (In,Ga)—Se films with repeatability and controllable molar ratios of (In,Ga) to Se are provided. Such layers are used in fabrication of semiconductor and electronic devices such as thin film solar cells. In one embodiment, the present invention provides an alkaline electrodeposition solution that includes an In salt, a Se acid or oxide, a tartrate salt as complexing agent for the In species, and a solvent to electrodeposit an In—Se film possessing sub-micron thickness on a conductive surface.

Abstract: A multi step process, which forms a Group VIA material layer, such as a selenium (Se) layer, having a thickness greater than 500 nanometers. The process includes electroplating a Se material layer, which has an amorphous micro-structure and which exhibits high electrical resistivity, on a workpiece and subsequently annealing the Se layer. Annealing process transforms the amorphous structure of the Se layer into a crystalline structure which is conductive. After the annealing, another Se layer can be electroplated onto the annealed Se layer. The electroplating and annealing steps can be repeated until the desired Se layer thickness is reached.

Abstract: A method of forming a metal telluride (MTe) film on a base where M is Cd and optionally additionally may include at least one of Zn, Hg, Mn and Mg, involves depositing a Te-rich precursor layer on a base and reaction of the Te-rich precursor layer with an M-containing material at elevated temperature. The Te-rich precursor film is one of a MTex compound film with an x value larger than 1, a composite film comprising MTe and Te, and a composite film comprising a MTex compound film with an x value larger than 1. In a preferred embodiment the Te-rich precursor layer is electrodeposited. In another preferred embodiment both the Te-rich precursor layer and the M-containing material are electrodeposited.

Abstract: A method of forming an ohmic contact to a surface of a Cd and Te containing compound film as may be found, for example in a photovoltaic cell. The method comprises forming a Te-rich layer on the surface of the Cd and Te containing compound film; depositing an interface layer on the Te-rich layer; and laying down a contact layer on the interface layer. The interface layer is composed of a metallic form of Zn and Cu.

Abstract: A method of fabricating a solar cell involves electroplating a Group IIB-VIA material as a first or sub-layer over a junction partner layer, and then forming a second layer, also of a Group IIB-VIA material over the sub-layer. Both the sub-layer and the second layer comprise Te. The electroplating is performed at relatively low temperatures, as for example, below 100° C. Forming the sub-layer by low temperature electroplating produces a small grained compact film that protects the interface between the sub-layer and the junction partner during the formation of the second layer. The second layer may be formed by physical vapor deposition or ink deposition. A solar cell has a first layer of a stoichiometric Group IIB-VIA material formed on a CdS film, and a second layer of a Group IIB-V1A material. Both the first and second layers contain Te. The first layer may comprise CdTe with a grain size small than 0.5 microns and the second layer may comprise CdTe with a grin size in the range of 1-5 microns.

Abstract: Described in one embodiment is a system that has a multiple number of different stations for forming solar cell modules. Described in another embodiment is a system that includes a cutting station, a setting station, and an interconnection station to create different series-connected flexible solar cell modules. Described in still another embodiment is a monolithically integrated multi-module power supply.

Abstract: An electrochemical deposition method and electrolyte to plate uniform, defect free and smooth gallium films are provided. In a preferred embodiment, the electrolyte may include a solvent that comprises water and at least one monohydroxyl alcohol, a gallium salt, and an acid to control the solution pH and conductivity. The method electrodeposits a gallium film possessing sub-micron thickness on a conductive surface. Such gallium layers are used in fabrication of semiconductor and electronic devices such as thin film solar cells.

Abstract: A thin film solar cell including a Group IBIIIAVIA absorber layer on a defect free base including a stainless steel substrate is provided. The stainless steel substrate of the base is surface treated to reduce the surface roughness such as protrusions that cause shunts. In one embodiment, the surface roughness is reduced by coating surface with a thin silicon dioxide which fills the cavities and recesses around the protrusions and thereby reducing the surface roughness. After the silicon dioxide film is formed, a contact layer is formed over the ruthenium layer and the exposed portions of the substrate to complete the base.

Abstract: The present invention advantageously provides for, in different embodiments, low-cost deposition techniques to form high-quality, dense, well-adhering Group IBIIIAVIA compound thin films with macro-scale as well as micro-scale compositional uniformities. It also provides methods to monolithically integrate solar cells made on such compound thin films to form modules. In one embodiment, there is provided a method of growing a Group IBIIIAVIA semiconductor layer on a base, and includes the steps of depositing on the base a nucleation and/or a seed layer and electroplating over the nucleation and/or the seed layer a precursor film comprising a Group IB material and at least one Group IIIA material, and reacting the electroplated precursor film with a Group VIA material. Other embodiments are also described.

Abstract: Described is an electrodeposition solution for deposition of a Group IB-IIIA thin film on a conductive surface. In a preferred embodiment, the electrodeposition solution comprises a solvent; a Group IB material source that dissolves in the solvent and provides a Group IB material; a Group IIIA material source that dissolves in the solvent and provides a Group IIIA material; and a blend of at least two complexing agents, one of the at least two complexing agent forming a complex with the Group IB material and the other one of the at least two complexing agent forming a complex with the Group IIIA material; wherein the pH of the solution is at least 7.

Abstract: The present invention provides methods of manufacturing a high efficiency solar cell. In one embodiment, in a solar cell having a grid pattern that channels current, a defect causes an undesired current flow is removed by mechanically removing a portion of the grid pattern, thereby passivating the defect by removing a segment of the solar cell adjacent the defect. The segment also includes the front and back portions of the solar cell at the location of the defect without including the defect.

Abstract: An electrochemical deposition method and electrolyte to plate uniform, defect free and smooth gallium films are provided. In a preferred embodiment, the electrolyte may include a solvent that comprises water and at least one monohydroxyl alcohol, a gallium salt, and an acid to control the solution pH and conductivity. The method electrodeposits a gallium film possessing sub-micron thickness on a conductive surface. Such gallium layers are used in fabrication of semiconductor and electronic devices such as thin film solar cells.

Abstract: A method of forming a doped Group IBIIIAVIA absorber layer for solar cells by reacting a partially reacted precursor layer with a dopant structure. The precursor layer including Group IB, Group IIIA and Group VIA materials such as Cu, Ga, In and Se are deposited on a base and partially reacted. After the dopant structure is formed on the partially reacted precursor layer, the dopant structure and partially reacted precursor layer is fully reacted. The dopant structure includes a dopant material such as Na.

Abstract: A deposition method and a system are provided to deposit a CdS buffer layer on a surface of a solar cell absorber layer of a flexible workpiece from a process solution including all chemical components of the CdS buffer layer material. CdS is deposited from the deposition solution while the flexible workpiece is heated and elastically shaped by a heated shaping plate to retain the process solution on the solar cell absorber layer. The flexible workpiece is elastically shaped by pulling a back surface of the flexible workpiece into a cavity area in the heated shaping plate using an attractive force.

Abstract: The present invention relates to methods and apparatus for providing composition control to thin compound semiconductor films for radiation detector and photovoltaic applications. In one aspect of the invention, there is provided a method in which the molar ratio of the elements in a plurality of layers are detected so that tuning of the multi-element layer can occur to obtain the multi-element layer that has a predetermined molar ratio range. In another aspect of the invention, there is provided a method in which the thickness of a sub-layer and layers thereover of Cu, In and/or Ga are detected and tuned in order to provide tuned thicknesses that are substantially the same as pre-determined thicknesses.

Abstract: Described is an electrodeposition solution for deposition of a Group IB-IIIA thin film on a conductive surface. In a preferred embodiment, the electrodeposition solution comprises a solvent; a Group IB material source that dissolves in the solvent and provides a Group IB material; a Group IIIA material source that dissolves in the solvent and provides a Group IIIA material; and a blend of at least two complexing agents, one of the at least two complexing agent forming a complex with the Group IB material and the other one of the at least two complexing agent forming a complex with the Group IIIA material; wherein the pH of the solution is at least 7.

Abstract: In one embodiment, a continuous electroless deposition method and a system to form a solar cell buffer layer with a varying composition through its thickness are provided. The composition of the buffer layer is varied by varying the composition of a chemical bath deposition solution applied onto an absorber surface on which the buffer layer with varying composition is formed. In one example, the buffer layer with varying composition includes a first section containing CdS, a second section containing CdZnS formed on top of the already deposited CdS, and a third section containing ZnS is formed on the second section All the process steps are applied in a roll-to-roll fashion. In another embodiment, a transparent conductive layer including a first transparent conductive film such as aluminum doped zinc oxide and a second transparent conductive film such as indium tin oxide is deposited over the buffer layer with the varying composition.