A photovoltaic cell may include a hydrogenated amorphous silicon layer including a n-type doped region and a p-type doped region. The n-type doped region may be separated from the p-type doped region by an intrinsic region. The photovoltaic cell may include a front transparent electrode connected to the n-type doped region, and a rear electrode connected to the p-type doped region. The efficiency may be optimized for indoor lighting values by tuning the value of the H2/SiH4 ratio of the hydrogenated amorphous silicon layer.

Systems and methods are presented including solar cells or solar sheets having textured coversheets that provide increased light collection efficiency. Some embodiments include a textured solar sheet configured for installation on a surface of a UAV or on a surface of a component of a UAV. The textured solar sheet includes a plurality of solar cells and a polymer layer to which the plurality of solar cells are attached. Some embodiments include a kit for supplying solar power in a battery-powered or fuel cell powered unmanned aerial vehicle (UAV) by incorporating flexible, textured solar cells into a component of a UAV, affixing flexible, textured solar cells to a surface of a UAV, or affixing flexible, textured solar cells to a surface of a component of a UAV. The kit also includes a power conditioning system configured to operate the solar cells within a desired power range and configured to provide power having a voltage compatible with an electrical system of the UAV.

The invention relates to a semiconductor structure made of a substrate and a semiconductor layer which are bonded integrally to each other via a thermally and/or chemically cured adhesive. Likewise, the invention relates to a method for the production of such integral bonds. Use in such semiconductor structures, in particular as solar cell or solar cell module.

An engineered substrate comprises: a seed layer made of a first semiconductor material for growth of a solar cell; a support substrate comprising a base and a surface layer epitaxially grown on a first side of the base, the base and the surface layer made of a second semiconductor material; a direct bonding interface between the seed layer and the surface layer; wherein a doping concentration of the surface layer is higher than a predetermined value such that the electrical resistivity at the direct bonding interface is below 10 mOhm.Math.cm.sup.2, preferably below 1 mOhm.Math.cm.sup.2; and wherein a doping concentration of the base as well as the thickness of the engineered substrate are such that absorption of the engineered substrate is less than 20%, preferably less than 10%, and total area-normalized series resistance of the engineered substrate is less than 10 mOhm.Math.cm.sup.2, preferably less than 1 mOhm.Math.cm.sup.2.

Flat top beam laser processing schemes are disclosed for producing various types of hetero-junction and homo-junction solar cells. The methods include base and emitter contact opening, back surface field formation, selective doping, and metal ablation. Also, laser processing schemes are disclosed that are suitable for selective amorphous silicon ablation and selective doping for hetero-junction solar cells. These laser processing techniques may be applied to semiconductor substrates, including crystalline silicon substrates, and further including crystalline silicon substrates which are manufactured either through wire saw wafering methods or via epitaxial deposition processes, that are either planar or textured/three-dimensional. These techniques are highly suited to thin crystalline semiconductor, including thin crystalline silicon films.

Various laser processing schemes are disclosed for producing various types of hetero-junction and homo-junction solar cells. The methods include base and emitter contact opening, selective doping, metal ablation, annealing to improve passivation, and selective emitter doping via laser heating of aluminum. Also, laser processing schemes are disclosed that are suitable for selective amorphous silicon ablation and selective doping for hetero-junction solar cells. Laser ablation techniques are disclosed that leave the underlying silicon substantially undamaged. These laser processing techniques may be applied to semiconductor substrates, including crystalline silicon substrates, and further including crystalline silicon substrates which are manufactured either through wire saw wafering methods or via epitaxial deposition processes, or other cleavage techniques such as ion implantation and heating, that are either planar or textured/three-dimensional. These techniques are highly suited to thin crystalline semiconductor, including thin crystalline silicon films.

The present invention refers to a photovoltaic cell (1) comprising a heterojunction with a base layer (L4, L4′, L4″) made from an Aluminium-Ar-senic-basedalloy and an emitter layer (L3, L3′) made from an Indium-Phosphorous based alloy wherein the emitter layer (L3, L3′) has a thickness smaller than 100 nm and acts as a passivation layer to prevent oxidation of the base layer and reduces surface recombination (L4, L4′, L4″).

According to one aspect of the disclosed subject matter, a monolithically isled solar cell is provided. The solar cell comprises a semiconductor layer having a light receiving frontside and a backside opposite the frontside and attached to an electrically insulating backplane. A trench isolation pattern partitions the semiconductor layer into electrically isolated isles on the electrically insulating backplane. A first metal layer having base and emitter electrodes is positioned on the semiconductor layer backside. A patterned second metal layer providing cell interconnection and connected to the first metal layer by via plugs is positioned on the backplane.

An engineered substrate comprising: a seed layer made of a first semiconductor material for growth of a solar cell; a first bonding layer on the seed layer; a support substrate made of a second semiconductor material; a second bonding layer on a first side of the support substrate; a bonding interface between the first and second bonding layers; the first and second bonding layers each made of metallic material; wherein doping concentration and thickness of the engineered substrate, in particular, of the seed layer, the support substrate, and both the first and second bonding layers, are selected such that the absorption of the seed layer is less than 20%, preferably less than 10%, as well as total area-normalized series resistance of the engineered substrate is less than 10 mOhm.Math.cm.sup.2, preferably less than 5 mOhm.Math.cm.sup.2.

A method for assembling a solar module structure comprises patterning a frontside and a backside of a double-sided printed circuit board coated with metallic foils according to desired frontside and backside interconnect layouts; applying a first coating layer to the rear side of a plurality of three-dimensional thin-film solar cells, each three-dimensional thin-film solar cell comprising: a three-dimensional thin-film solar cell substrate comprising emitter junction regions and doped base regions; emitter metallization and base metallization regions; the three-dimensional thin-film solar cell substrate comprising a plurality of single-aperture unit cells; placing the three-dimensional thin-film solar cells on the frontside of the double-sided printed circuit board; preparing a solar module assembly, comprising: a glass layer; a top encapsulant layer; the plurality of three-dimensional thin-film solar cells on the frontside of the double-sided printed circuit board; a rear encapsulant layer; a protective back plate; and sealing and packaging the solar module assembly.