TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Device: In the photovoltaic device, a back passivation layer is formed on a back surface of the crystalline semiconductor body, a back surface field layer or a back-sided emitter is formed on the back passivation layer, a back electrode is formed on the back surface field layer or on the back-sided emitter, where the back electrode comprises a back-sided transparent conductive material stack and a metallic contact layer, where the back-sided transparent conductive material stack is a stack of at least two transparent conductive components having different compositions, and where the back-sided transparent conductive material stack comprises a back-sided first transparent conductive layer comprising a third base material with a third doping and having a non-stoichiometric composition with a first deviation from stoichiometry, where the third base material is chosen from the group including indium oxide, zinc oxide, tin oxide, and cadmium oxide, and - a back-sided second transparent conductive layer or structure comprising the third base material or a fourth base material, the third or fourth base material having the third doping or a fourth doping being different from the third doping and having a non-stoichiometric composition, where the composition of the fourth base material is different from the composition of the third base material and where the composition of the third base material has a fourth deviation from stoichiometry being different from the third deviation from stoichiometry, respectively, where the average carrier concentration of the whole back-sided transparent conductive material stack is between 1x1020 cm-3 and 2x1020 cm-3; the refractive indices (n) of the back-sided first transparent conductive layer and of the back-sided second transparent conductive layer or structure are in the same range, where n not greater than 2 at a wavelength of about 550 nm; and the carrier mobility in the back-sided first transparent conductive layer is higher than the carrier mobility in the back-sided second transparent conductive layer or structure if the layers/structure have a comparable thickness. The front-sided first transparent conductive layer is formed on the emitter or on the front surface field layer, and/or the back-sided first transparent conductive layer is formed on the back surface field layer or on the back-sided emitter. At least a part of the second transparent conductive layer or structure is formed on the whole surface of the photovoltaic device. At least a part of the second transparent conductive layer or structure is localized under at least parts of the front grid metallization. The transparent conductive material stack further comprises a third transparent conductive layer formed on the front side of the photovoltaic device between the emitter or the front surface field layer and the front-sided transparent conductive material stack and/or formed on a back side of the photovoltaic device between the back surface field layer or the back-sided emitter and the back-sided transparent conductive material stack, where the third transparent conductive layer has a work function being higher if put on a p-doped emitter or back-sided emitter or back surface field layer or front surface field layer than the work function of the layers/structures of the transparent conductive material stack or being lower if put on a n-doped emitter or back-sided emitter or back surface field layer or front surface field layer than the work function of the layers/structures of the transparent conductive material stack. The second transparent conductive layer or structure and/or the third transparent conductive layer consist(s) of at least one material selected from indium oxide, zinc oxide, tin oxide, and cadmium oxide. The front-sided second transparent conductive layer or structure is covered by an additional antireflection coating. The additional antireflection coating consists of at least one material selected from magnesium fluoride (MgF2), silicon dioxide (SiO2), zirconium dioxide (ZrO2), titanium dioxide (TiO2), cerium fluoride (CeF3), and aluminum oxide (Al2O3). Preferred Process: Manufacturing photovoltaic device with hetero-junction further involves forming a back passivation layer on a back surface of the crystalline semiconductor body, forming a back surface field layer or a back-sided emitter on the back passivation layer, forming a metallic contact layer on the surface field layer or on the back-sided emitter, and providing a back electrode on the back surface field layer by forming a back-sided transparent conductive material stack and forming a metallic contact layer, where the back-sided transparent conductive material stack is provided by forming a stack of at least two transparent conductive components having different compositions, comprising the steps of - forming a back-sided first transparent conductive layer, where the back-sided first transparent conductive layer is formed using a third base material with a third doping and having a non-stoichiometric composition with a third deviation from stoichiometry, and where the third base material is chosen from the group of materials including indium oxide, zinc oxide, tin oxide, and cadmium oxide, and - forming a back-sided second transparent conductive layer or structure, where the back-sided second transparent conductive structure is formed using the third base material or a fourth base material, the third or fourth base material having the third doping or a fourth doping being different from the third doping and having a non-stoichiometric composition, where the composition of the fourth base material is different from the composition of the third base material and where the composition of the third base material has a fourth deviation from stoichiometry being different from the third deviation from stoichiometry, respectively, where the average carrier concentration of the whole back-sided transparent conductive material stack is between 1x1020 cm-3 and 2x1020 cm-3; the refractive indices (n) of the back-sided first transparent conductive layer and of the back-sided second transparent conductive layer or structure are in the same range, where n not greater than 2 at a wavelength of about 550 nm; and the carrier mobility in the back-sided first transparent conductive layer is higher than the carrier mobility in the back-sided second transparent conductive layer or structure if the layers/structure have a comparable thickness. The second transparent conductive structure is formed as a layer on the whole surface of the first transparent conductive layer or on the whole surface of the emitter or on the whole front surface field layer and is structured by etching, where the front grid metallization acts as a mask during the etch process. The second transparent conductive structure is deposited as a layer on the whole surface of the first transparent conductive layer or on the whole surface of the emitter or on the whole front surface field layer and is structured by etching, and the front grid metallization is aligned on the structured second transparent conductive layer or structure. Second transparent conductive layer or structure is deposited through a mask on the first transparent conductive layer or on the emitter or on the front surface field layer, and the front grid metallization is aligned on the localized second transparent conductive structure. A third transparent conductive layer is formed between the emitter or the front surface field layer and the transparent conductive material stack on the front side of the photovoltaic device and/or between the back surface field layer or the back-sided emitter and the transparent conductive material stack on the back side of the photovoltaic device, where the third transparent conductive layer has a work function being higher if put on a p-doped emitter or back-sided emitter or back surface field layer or front surface field layer than the work function of the layers/structures of the transparent conductive material stack or being lower if put on a n-doped emitter or back-sided emitter or back surface field layer or front surface field layer than the work function of the layers/structures of the transparent conductive material stack. The steps of the method are provided in the following order, forming the emitter or on the front surface field layer, forming the front-sided first transparent conductive layer or structure on the emitter or the front surface field layer, forming the front-sided second transparent conductive layer on the front-sided first transparent conductive layer or structure, and forming the front grid metallization on top of the front-sided second transparent conductive layer or structure; or the steps of the method are provided in the following order forming the emitter or the front surface field layer, forming the front-sided second transparent conductive layer or structure on the emitter or on the front surface field layer, forming the front grid metallization on top of the front-sided second transparent conductive layer or structure, and forming the front-sided first transparent conductive layer on the front grid metallization. The front-sided transparent conductive material stack is covered by an additional antireflection coating, and contacts of the front grid metallization are protected by a mask or by a soluble ink provided on the contacts, respectively, during the formation of the additional antireflection coating.