Abstract: In some embodiments, a method of forming a photovoltaic cell includes (1) forming a cleave plane in a donor body so as to define a lamina to be bonded to a receiver element and exfoliated from the donor body; (2) prior to bonding, pre-heating the donor body without the receiver element to a temperature of greater than about 200° C. for a first time period that is less than a time period required for exfoliation of the lamina from the donor body; (3) cooling the donor body after pre-heating the donor body; (4) bonding the donor body to the receiver element; and (5) heating the bonded donor body and receiver element for a second time period so as to complete the exfoliation of the lamina from the donor body. Numerous other aspects are provided.

Abstract: Ion implanters are especially suited to meet process dose and energy demands associated with fabricating photovoltaic devices by ion implantation followed by cleaving.

Abstract: Methods for bonding a donor wafer to a receiver element and transferring a lamina from the donor wafer to the receiver element are disclosed herein. The donor wafer may be, for example, a monocrystalline silicon wafer with a thickness of from about 300 microns to about 1000 microns, and the lamina may be may be less than 100 microns thick. The receiver element may be composed of, for example, metal or glass, and the receiver element may have dissimilar thermal expansion properties from the lamina. Although the lamina and the receiver element may have dissimilar thermal expansion properties, the methods disclosed herein maintain the integrity of the bond between the lamina and the receiver element.

Abstract: Ion implanters are especially suited to meet process dose and energy demands associated with fabricating photovoltaic devices by ion implantation followed by cleaving.

Abstract: A very thin photovoltaic cell is formed by implanting gas ions below the surface of a donor body such as a semiconductor wafer. Ion implantation defines a cleave plane, and a subsequent step exfoliates a thin lamina from the wafer at the cleave plane. A photovoltaic cell, or all or a portion of the base or emitter of a photovoltaic cell, is formed within the lamina. In preferred embodiments, the wafer is affixed to a receiver before the cleaving step. Electrical contact can be formed to both surfaces of the lamina, or to one surface only.

Abstract: Ion implanters are especially suited to meet process dose and energy demands associated with fabricating photovoltaic devices by ion implantation followed by cleaving.

Abstract: Ion implanters are especially suited to meet process dose and energy demands associated with fabricating photovoltaic devices by ion implantation followed by cleaving.

Abstract: A semiconductor donor body is affixed to a receiver element, and a thin semiconductor lamina is cleaved from the donor body, remaining affixed to the receiver element. A photovoltaic assembly is fabricated which includes the lamina and the receiver element, wherein a photovoltaic cell comprises the lamina. The bond between the semiconductor donor body and the receiver element must survive processing to complete the cell, as well as eventual assembly, transport, and operation in a finished photovoltaic module. It has been found that inclusion of a conductive layer such as titanium or aluminum aids bonding between the semiconductor donor body and the receiver element. In some embodiments, the conductive layer may also serve as an electrical contact and/or as a reflective layer.

Abstract: A very thin photovoltaic cell is formed by implanting gas ions below the surface of a donor body such as a semiconductor wafer. Ion implantation defines a cleave plane, and a subsequent step exfoliates a thin lamina from the wafer at the cleave plane. A photovoltaic cell, or all or a portion of the base or emitter of a photovoltaic cell, is formed within the lamina. In preferred embodiments, the wafer is affixed to a receiver before the cleaving step. Electrical contact can be formed to both surfaces of the lamina, or to one surface only.

Abstract: A very thin photovoltaic cell is formed by implanting gas ions below the surface of a donor body such as a semiconductor wafer. Ion implantation defines a cleave plane, and a subsequent step exfoliates a thin lamina from the wafer at the cleave plane. A photovoltaic cell, or all or a portion of the base or emitter of a photovoltaic cell, is formed within the lamina. In preferred embodiments, the wafer is affixed to a receiver before the cleaving step. Electrical contact can be formed to both surfaces of the lamina, or to one surface only.

Abstract: A very thin photovoltaic cell is formed by implanting gas ions below the surface of a donor body such as a semiconductor wafer. Ion implantation defines a cleave plane, and a subsequent step exfoliates a thin lamina from the wafer at the cleave plane. A photovoltaic cell, or all or a portion of the base or emitter of a photovoltaic cell, is formed within the lamina. In preferred embodiments, the wafer is affixed to a receiver before the cleaving step. Electrical contact can be formed to both surfaces of the lamina, or to one surface only.

Abstract: A very thin photovoltaic cell is formed by implanting gas ions below the surface of a donor body such as a semiconductor wafer. Ion implantation defines a cleave plane, and a subsequent step exfoliates a thin lamina from the wafer at the cleave plane. A photovoltaic cell, or all or a portion of the base or emitter of a photovoltaic cell, is formed within the lamina. In preferred embodiments, the wafer is affixed to a receiver before the cleaving step. Electrical contact can be formed to both surfaces of the lamina, or to one surface only.

Abstract: A very thin photovoltaic cell is formed by implanting gas ions below the surface of a donor body such as a semiconductor wafer. Ion implantation defines a cleave plane, and a subsequent step exfoliates a thin lamina from the wafer at the cleave plane. A photovoltaic cell, or all or a portion of the base or emitter of a photovoltaic cell, is formed within the lamina. In preferred embodiments, the wafer is affixed to a receiver before the cleaving step. Electrical contact can be formed to both surfaces of the lamina, or to one surface only.

Abstract: A social networking website logs information about actions taken by members of the website. For a particular member of the website, the website presents targeted ads based on actions by the member and one or more characteristics of the member. The social networking website maintains a profile associated with the member which describes characteristics of the member, such as age, geographic location, employment, educational history and interests. The social networking website compares the member profile to targeting criteria for a plurality of advertising requests and determines the advertising requests that match the member profile and generate the most revenue for the social networking website. When presenting a member with an ad, the website may optimize advertising revenue by selecting an ad from the received ads that will maximize the expected value of the ad.

Abstract: A method for confirming a request for an association with an organization by a user of a web-based social network is disclosed. In one embodiment, the request includes an e-mail address not controlled by the organization. The request may also be part of an application for membership with the web-based social network. A determination is made whether the request is accepted based at least partially on a specified number of prior requests for association with the organization or being identified as a member of the organization by another user already a member of the organization. The organization may be a high school, a college, a university, a business, a non-profit company, or any other group of people who may desire to associate with each other.

Abstract: A system and method for determining a trust level for a non-approved user in a social network is described. The method includes monitoring requests for social network interactions between an approved user and the non-approved user and determining if each interaction requested is of a first type or a second type. The method further includes increasing a first trust value when the interaction requested is of the first type and increasing a second trust value when the interaction requested is of the second type. The method further includes determining the trust level based on the first trust value and the second trust value. The method further includes changing the status of the non-approved user to an approved user based on the trust level, the first trust value and/or the second trust value.

Abstract: A method for forming a friction stir welded assembly is provided, as is an associated component assembly formed according to such a method. The method includes coating surface portions of one or more untreated articles with a coating material. Thereafter, the articles are friction stir welded to form an assembly. A thermal treatment is performed before or after the welding operation, e.g., to simultaneously heat treat the articles and cure the coating.

Abstract: An ion implanter for creating a ribbon or ribbon-like beam by having a scanning device that produces a side to side scanning of ions emitting by a source to provide a thin beam of ions moving into an implantation chamber. A workpiece support positions a workpiece within the implantation chamber and a drive moves the workpiece support up and down through the thin ribbon beam of ions perpendicular to the plane of the ribbon to achieve controlled beam processing of the workpiece. A control includes a first control output coupled to said scanning device to limit an extent of side to side scanning of the ion beam to less than a maximum amount and thereby limit ion processing of the workpiece to a specified region of the workpiece and a second control output coupled to the drive simultaneously limits an extent of up and down movement of the workpiece to less than a maximum amount and to cause the ion beam to impact a controlled portion of the workpiece.