Abstract: An intermediate band solar cell is provided. The intermediate band material of the intermediate band solar cell consists of a collection of quantum dots of a semiconductor material that are immersed in a volume of a second semiconductor material. The first semiconductor material has a rock salt-type crystalline structure, and the second semiconductor material has a zinc blende structure. The quantum dots are produced by the immiscibility of the first semiconductor material in the second semiconductor material. A combination of the first and second semiconductor materials with a very similar lattice constant can therefore be selected such that the layer of intermediate band material does not have mechanical stress accumulation.

Abstract: A high throughput reactor for the mass production of wafers through chemical vapor deposition, mainly to form silicon epitaxies for the photovoltaic industry, is described. Main innovation is a high susceptor stacking density: several graphite susceptors are placed vertically and parallel to one another, electrically interconnected, and are heated by Joule effect. Electrical current gets to the susceptors from the current source through specially designed feedthroughs, which connect the cold room outside the deposition chamber with the hot susceptors. Gas flows vertically between susceptors. The substrates on which deposition occurs are placed on the susceptors. Below the susceptors a pre-chamber is found, in which entering gas calms down and distributes homogeneously. Susceptors and pre-chamber are placed inside a stainless steel chamber, which is internally covered by a reflecting material, and externally kept cold by water.

Abstract: Method for manufacturing of optoelectronic devices based on thin-film, intermediate band materials, characterized in that it comprises, at least, the following steps: a first stage wherein a substrate (1) is coated with a metal layer acting as electrode (2); a second stage, whereby atop the metal layer (2) a p-type semiconductor (3) is deposited; and a third stage, whereby the intermediate band material is processed; and wherein such an intermediate band material comprises nanoscopic structures (4) of multinary material of the type (Cu,Ag)(Al,Ga,In)(S,Se,Te)2 embedded in a matrix (5) of a similar composition, except for the absence of, at least, one cationic species present in the nanostructure.

Abstract: This invention describe a process for obtaining thin films of intermediate band semiconductor materials consisting of obtaining a target of compressed particles of the said material for its use in sputtering equipment. The target is obtained by means of the thermal process of a mixture of semiconductor material components, following a specific profile of temperatures and times, in order to obtain a material in a polycrystalline form of the same composition as the intermediate band semiconductor material. The polycrystalline material is disintegrated again by means of mechanical processes in the form of a powder and is then compacted, through the application of a suitable pressure in order to form a target.

Abstract: It consists of a quantum dot intermediate band solar cell with light coupling by diffraction. In the structure of the cell, the rear metalic contact (7) is separated from the semiconductor (1) by a low refraction index layer (8). It also contains a number of grooves (9) on the front face covered by one or more antireflecting layers (10) which are also part of the diffractive structure. The grooves (9) are designed in such a way that they difract on the infrared range the light cone coming from a concentrator, leaning them as much as possible. In this way, the luminous electromagnetic power flux is increased facilitating its absorption by the quantum dot layer (4). Layer (8) produces a total internal reflection of the rays inclined by (9).

Abstract: A high throughput reactor for the mass production of wafers through chemical vapor deposition, mainly to form silicon epitaxies for the photovoltaic industry, is described. main innovation is a high susceptor stacking density: several graphite susceptors are placed vertically and parallel to one another, electrically interconnected, and are heated by Joule effect. Electrical current gets to the susceptors from the current source through specially designed feedthroughs, which connect the cold room outside the deposition chamber with the hot susceptors. Gas flows vertically between susceptors. The substrates on which deposition occurs are placed on the susceptors. Below the susceptors a pre-chamber is found, in which entering gas calms down and distributes homogeneously. Susceptors and pre-chamber are placed inside a stainless steel chamber, which is internally covered by a reflecting material, and externally kept cold by water.

Abstract: Procedure to obtain semiconductor materials with electronic levels close to the mid-bandgap (deep levels) which do not suffer from the non-radiative recombination by multiple phonon emission (MPE) associated to the existence of that kind of levels. The procedure consist in doping by any means the semiconductor with a density sufficiently high of the impurities producing the deep level, so that a Mott transition of the electron wavefunctions representing the localized states in the impurities is induced, in such a way that these wavefunctions become distributed across the whole semiconductor and are shared by all the impurities. When this happens, local charge density variations, and thus non-radiative recombination by MPE, disappear. Based on the resulting materials (semiconductors with three separate energy bands and radiative behavior (1), (2) and (3)) different optoelectronic devices can be fabricated (solar cells, photodetectors, lasers, etc.

Abstract: The invention relates to a solar cell containing a semiconductor (1) with an intermediate band (2) that is half filled with electrons, located between two layers of ordinary n type (3) and p type (4) semiconductors. When lighted, electron-hole pairs are formed either by a photon that absorbs the necessary energy (5) or by two photons (6,7) that absorb less energy which pump an electron from the valence band to the intermediate band (8) and from the latter to the conductance band (9). An electrical current is generated that exits on the p side and returns via the n side. The n and p layers also prevent the intermediate band from contacting the outer metal connections, which would have resulted in a short-circuit. Said cell converts solar energy into electricity in a more efficient manner than conventional cells and contributes to improvement of the photovoltaic devices.

Abstract: A light confining cavity collects much of the radiation reflected by a receiver, absorbing it imperfectly, and casts it again on the same receiver or on other receivers by means of an optical system. Only light in a bundle of rays of limited angular spread can escape from this cavity, which allows an entry aperture relatively large. Thus, the irradiance at the entry aperture may be low, and in some cases even lower than the irradiance at the absorber. In this way the requirements for the cavity materials and for the concentrating system feeding light to the cavity can be relaxed. The invention is of special interest in photovoltaic conversion devices because it improves the absorption of the solar cells and achieves higher conversion efficiency for photons of different energies by using solar cells of different materials.

Abstract: A planar solar cell photovoltaically active on both sides is positioned in a solar concentrator capable of simultaneously illuminating both sides of the cell. The cell is immersed in a transparent liquid that enhances solar energy concentration and aids in removing undesirable heat from the cell. The solar cell, having two photovoltaically active sides, can be constituted by a n+pn+ structure or by a n+pp+ structure. Electrically conductive metal grids serving as cathode and anode connections are formed on both sides of the cell. The grid apertures advantageously allow the light to enter into the appropriate semiconductor regions. In the case of a n+pn+ structure, window means in the n+ layers are provided to permit electrical contact between the anode grids and the p region. Solar cells with complementary dopings, for example p+np+, are also possible.