TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: Manufacturing photovoltaic solar cells includes growing at least one semiconductor layer of intrinsic, p-type or n-type material, which is compounded of at least two layers of III-V materials in an alternating super structure; growing at least four different compounded III-V monocrystalline semiconductor layers on the silicon substrate; growing at least five different compounded III-V monocrystalline semiconductor layers on the silicon substrate; growing the first semiconductor layer so that the transition between the silicon substrate and the first grown semiconductor layer includes a defect layer which provides a low content of defects in the grown semiconductor layer; growing the semiconductor layers so that the transition between two grown semiconductor layers contain a defect layer which provides a low content of defects in the last grown semiconductor layer; growing a second semiconductor layer consisting of AlSb, GaSb, or InSb on the silicon substrate; growing a second semiconductor layer consisting of AlInSb, AlGaSb, GaInSb or AlGaInSb on the silicon substrate; growing a second semiconductor layer consisting of AlAsxSb1-x, GaASxSb1-x, InAsxSb1-x, AlInAsxSb1-x, AlGaAsxSb1-x, GaInASxSb1-x, or AlGaInASxSb1-x with x is greater than or equal to 0 but less than 0.5 on the silicon substrate; growing a third semiconductor layer consisting of AlAs, GaAs or InAs on the silicon substrate; growing a third semiconductor layer consisting of AlInAs, AlGaAs, GaInAs or AlGaInAs on the silicon substrate; or growing a third semiconductor layer consisting of AlAsxSb1-x, GaAsxSb1-x, InASxSb1-x, GaInASxSb1-x or AlGaInASxSb1-x with x less than or equal to 1 but greater than 0.5 on the silicon substrate. The method also comprises: (i) growing III-V material(s) having one or more p-n, p-i-n, p-p-n or p-n-n transition(s); (ii) growing the semiconductor layers so that at least two defect layer are formed between the different III-V materials between the silicon and the III-V transition; and (iii) using a silicon substrate which contains both p-type and n-type material. It includes using a silicon substrate having a p-n, p-i-n, p-p-n or p-n-n transition and grow semiconductor layers of III-V materials having one or more p-n, p-i-n, p-p-n or p-n-n transitions for providing a multi-transition solar cell. It includes growing the semiconductor layers so that two of the defect layers between the III-V materials are separated by at least one p- n, p-i-n, p-p-n or p-n-n transition. The method includes growing the semiconductor layers so that at least one III-V transition consist of AlAsxSb1-x, GaASxSb1-x, AlInASxSb1-x, AlGaAsxSb1-x, GaInAsxSb1-x, GaInAsxP1-x, AlGaInAsxP1-x and/or AlGaInAsxSb1-x with x less than or equal to 1 but greater than 0.5. It includes growing the semiconductor layers so that at least one III-V transition consists of AlAsxSb1-x, GaASxSb1-x, AlInAsxSb1-x, AlGaAsxSb1-x, GaInAsxSb1-x, GaInAsxP1-x, AlGaInAsxP1-x and/or AlGaInAsxSb1-x with x less than or equal to 1 but greater than 0.9. It includes doping the silicon substrate with boron (B), phosphorus (P), gallium (Ga), arsenic (As) and/or antimony (Sb) for forming intrinsic, p-type and/or n-type layers in the transition; using a silicon substrate having a 100-surface of crystallographic orientation with 1-5 degrees miscut; using a silicon substrate having a 100-surface of crystallographic orientation with 2-4 degrees miscut; using a silicon substrate having a Ill-surface of crystallographic orientation with 1-5 degrees miscut; using a silicon substrate having a 221-surface of crystallographic orientation; adding silicon, beryllium, selenium or tellurium in amount(s) being less than 10 at% of the grown material; exposing the silicon substrate for damps of gallium, aluminum, indium, arsenic, antimony, phosphorus and/or nitrogen; doping/adding to at least two of the III-V materials with silicon, beryllium, selenium or tellurium for providing n-type and p-type contact layers; arranging metal contacts of lead (Pd), Sb, titanium (Ti), platinum (Pt), gold (Au), aluminum (Al), copper (Cu) and/or silver (Ag) in contact with the semiconductor layers on the silicon substrate; using a layer of silicon at the bottom, one layer of III-V material having a new grating constant over this and several layers of two III-V materials having a third grating constant over this again; growing III-V materials having a given fraction of their mutual grating constants for incorporating a set of defects in the transition between the different materials solving the fraction; arranging transitions there the material composition changes gradually from one composition to another; growing a thin layers of AlGaInAsSb, quaternary, ternary and/or binary layers which act as a defect stop grating which deflects the defects and prevent that they propagate through the structure; growing layers being thinner than the wave distribution function of the electron in the material, so that the electrons experience the material as an average material; or treating the material thermally for crystallizing remaining defects and possibly improve the charge carrying properties of the material, after the entire structure is grown. Preferred Cell: The photovoltaic solar cell(s) include(s) at least one semiconductor layer of intrinsic, p-type or n-type material, which is compounded of at least two layers of III-V materials in an alternating super structure. Photovoltaic solar cell(s) include(s) at least four different compounded III-V monocrystalline semiconductor layers on the silicon substrate, or at least five different compounded III-V monocrystalline semiconductor layers on the silicon substrate; photovoltaic solar cell(s) include(s) a transition between the silicon substrate and the first grown semiconductor layer containing a defect layer which provides a low content of defects in the grown semiconductor layer; photovoltaic solar cell(s) include(s) a transition between two grown semiconductor layers containing a defect layer which provides a low content of defects in the last grown semiconductor layer; or photovoltaic solar cell(s) include(s) a second semiconductor layer consisting of AlSb, GaSb, or InSb, AlInSb, AlGaSb, GaInSb or AlGaInSb, or AlAsxSb1-x, GaASxSb1-x, InASxSb1-x, AlInAsxSb1-x, AlGaAsxSb1-x, GaInAsxSb1-x or AlGaInAsxSb1-x with x is greater 0 but less than 5. The semiconductor layers of the photovoltaic solar cell(s) (34) include one or more p-n, p-i-n, p-p-n or p-n-n transition(s), at least two defect layers between the different III-V materials between the silicon substrate and the III-V transition, and that the silicon substrate contains both p-type and n-type material. The silicon substrate includes a p-n, p-i-n, p-p-n or p-n-n transition and semiconductor layers of III-V materials having one or more p-n, p-i-n, p-p-n or p-n-n transitions. Defect layers between the III-V materials are separated by at least one p-n, p-i-n, p-p-n or p-n-n transition. The silicon substrate is doped with B, P, Ga, As and/or Sb for forming intrinsic, p-type and/or n-type layers in the transition. The silicon substrate is provided with a 100-surface of crystallographic orientation with 1-5 degrees miscut, a 100-surface of crystallographic orientation with 2-4 degrees miscut, a 111-surface of crystallographic orientation with 1-5 degrees miscut, or a 221-surface of crystallographic orientation. One or more of the semiconductor layers are added silicon, beryllium, selenium or tellurium in amount(s) being less than 10 at% of the grown material. The silicon substrate at manufacturing has been exposed to damps of gallium, aluminum, indium, arsenic, antimony, phosphorus and/or nitrogen. At least two of the semiconductor layers are doped or added with silicon, beryllium, selenium or tellurium for providing n-type and p-type contact layers. The photovoltaic solar cell(s) is/are provided with metal contacts of Pd, Sb, Ti, Pt, Au, Al, Cu and/or Ag in contact with the semiconductor layers on the silicon substrate. The silicon substrate is arranged a semiconductor layer of III-V material having a new grating constant over this and several semiconductor layers of two III-V materials having a third and fourth grating constant over this again. The semiconductor layers are arranged to each other with a given fraction of their mutual grating constants for incorporating a set of defects in the transition between the different materials solving the fraction. Photovoltaic solar cell(s) include(s) transitions there the material composition changes gradually from one composition to another; photovoltaic solar cell(s) include(s) thin layers of AlGaInAsSb, quaternary, ternary and/or binary semiconductor layers which act as a defect stop grating which deflects the defects and prevent that they propagate through the structure; photovoltaic solar cell(s) include(s) semiconductor layers being thinner than the wave distribution function of the electron in the material, so that the electrons experience the material as an average material; or photovoltaic solar cell(s) has/have been treated thermally for crystallizing remaining defects and possibly improving the charge carrying properties of the material, after the entire structure is grown. Multi-functional solar cell includes one or more of the following absorbing medium/absorbers, concentrator system arranged for receiving either primary radiation/solar radiation or secondary radiation for generating electric effect, optical filters arranged for collecting secondary radiation which is reflecting and/or transmitting chosen wavelengths to absorbing medium/absorber and photovoltaic solar cell, respectively, or vice versa. Photovoltaic solar cell(s) and/or the absorber(s) are provided with one or more optical antireflection/reflection coatings to collect secondary radiation reflecting and transmitting chosen wavelengths back towards absorber and/or towards/into the solar cell(s), respectively. The absorbing medium/absorber has a circular or spherical design, such as a ball, cylinder or other enclosing chamber, and is provided with a narrow aperture for incoming solar radiation; the absorbing medium/absorber is plates. The medium/absorber is segmented in different geometrical parts which enclose each other, so that solar cells and filters are formed enclosing the absorber as a spherical object, or as an extension as a cylinder. The absorbing medium/absorber is made of and/or covered with silicon carbide, tantalum, molybdenum or wolfram, or the absorber being a gas, arranged in a suitable container, or a medium holding a higher temperature than what solid material are able to, for either increasing the absorption and/or reducing the wavelength of the secondary radiation. The concentrator system includes one or more frensel lenses, optical lenses, elliptical mirrors or similar optical arrangements. Absorber, filter, photovoltaic solar cell(s) and other optical components are arranged in a vacuum for protection against environmental impact, such as degradation from air, rain, salts, sand or similar. Layers in the photovoltaic solar cell include other materials than III-V for insulation or passivation of the III-V materials or the surfaces of these. Photovoltaic solar cell is/are enclosed or coated of silicon dioxide (SiO2), polymer, titanium dioxide (TiO2), aluminum oxide (Al2O3), silicon nitride (Si3N4) or similar materials for passivation and/or protection of this. The solar cell is arranged in contact with an active or passive thermal cooling element for reduction of the temperature of the solar cell, preventing heating of this or controlling the temperature of the solar cell. An external heating source is connected to the absorber for either controlling the temperature of this or heating it when solar radiation is not available, the absorber is heated by a combustion process between natural gas and air/oxygen, fuel and air/oxygen, hydrogen and air/oxygen or another chemical reaction developing heat, or the absorber is heated by liquid salts, metals or similar materials transporting heat from an external hating source, such as geothermal heat, heat pump, combustion plant or radioactive source. Concentrator, filters, photovoltaic solar cell or absorber is provided with an optical coating for changing reflection or transmission, possibly used for controlling this property.