A photovoltaic cell can include an interfacial layer in contact with a semiconductor layer.

The present invention relates to a method of manufacturing semiconductor materials comprising interface layers of group III-V materials in combination with Si substrates. Especially the present invention is related to a method of manufacturing semiconductor materials comprising GaAs in combination with Si(111) substrates, wherein residual strain due to different thermal expansion coefficient of respective materials is counteracted by introducing added layer(s) compensating the residual strain.

According to the embodiments provided herein, a method for scribing a layer stack of a photovoltaic device can include directing a laser scribing waveform to a film side of a layer stack. The laser scribing waveform can include pulse groupings that repeat at a group repetition period of greater than or equal to 1.5 .Math.s. Each pulse of the pulse groupings can have a pulse width of less than or equal to 900 fs.

A method of forming a Group II-VI multijunction semiconductor device comprises providing a Group IV substrate, forming a first subcell from a first Group II-VI semiconductor material, forming a second subcell from a second Group II-VI semiconductor material, and removing the substrate. The first subcell is formed over the substrate and has a first bandgap, while the second subcell is formed over the first subcell and has a second bandgap which is smaller than the first bandgap. Additional subcells may be formed over the second subcell with the bandgap of each subcell smaller than that of the preceding subcell and with each subcell preferably separated from the preceding subcell by a tunnel junction. Prior to the removal of the substrate, a support layer is affixed to the last-formed subcell in opposition to the substrate.

A method of fabricating a buffer layer of a photovoltaic device comprises: providing a substrate having a back contact layer disposed above the substrate and an absorber layer disposed above the back contact layer; depositing a metal layer on the absorber layer; and performing a thermal treatment on the deposited metal layer in an atmosphere comprising sulfur, selenium or oxygen, to form a buffer layer.

Disclosed are ultrathin layers of group II-VI semiconductors, group II-VI semiconductor superlattice structures, photovoltaic devices incorporating the layers and superlattice structures and related methods. The superlattice structures comprise an ultrathin layer of a first group II-VI semiconductor alternating with an ultrathin layer of at least one additional semiconductor, e.g., a second group II-VI semiconductor, or a group IV semiconductor, or a group III-V semiconductor.

The present invention proposes a method to form a gradient thin film using a spray pyrolysis technique. The method comprises providing a base substrate, preparing a spray aqueous solution by mixing at least two precursor compounds comprising at least two different elements and spraying the spray aqueous solution onto the base substrate. According to the present invention, the ratio of the concentration of the at least two different elements within the spray aqueous solution is varied while performing the method. In this way, a thin film having a gradient of elemental composition over its layer thickness may be formed.

A method for manufacturing a large-area thin film solar cell includes the steps of: (a) forming a first contact layer on a substrate; (b) forming a multi-layer metal precursor film on the first contact layer, which includes the sub-steps of (b1) sputtering a first multinary metal precursor layer on the first contact layer, the first multinary metal precursor layer containing Cu, Ga and KF, and (b2) sputtering an In-containing precursor layer on the first multinary metal precursor layer; and (c) subjecting the multi-layer metal precursor film to selenization to form an absorber layer having a chalcopyrite phase.

A photovoltaic device is disclosed including at least one Cadmium Sulfide Telluride (CdS.sub.xTe.sub.1−x) layer as are methods of forming such a photovoltaic device.

A method for passing photovoltaic current between a subcell formed from a single crystal Group ll-VI semiconductor material and a subcell formed from a single crystal Group IV semiconductor material, includes the steps of forming a first subcell by an epitaxial growth process, the first subcell having a first upper surface; forming a tunnel heterojunction between the first subcell and the second subcell, and tunneling carriers formed by light incident on the first and second subcells through the tunnel heterojunction, thereby permitting a photoelectric series current to flow through the first and second subcells.