NOVELTY - Photovoltaic device with a hetero-junction, comprises a front side for an incidence of light, a crystalline semiconductor body, a front passivation layer formed on a front surface of the crystalline semiconductor body, an emitter or a front surface field layer formed on the front passivation layer, a front-sided transparent conductive material stack, and a front grid metallization.    USE - The photovoltaic device is useful as solar cell.    ADVANTAGE - Photovoltaic device and its manufacturing method are provided, leading to a decrease of optical and electrical losses in hetero-junction solar cells caused by the transparent conductive material (TCM).    DETAILED DESCRIPTION - Photovoltaic device with a hetero-junction, comprises a front side for an incidence of light, a crystalline semiconductor body, a front passivation layer formed on a front surface of the crystalline semiconductor body, an emitter or a front surface field layer formed on the front passivation layer, a front-sided transparent conductive material stack, and a front grid metallization, where the front-sided transparent conductive material stack is a stack of at least two transparent conductive components having different compositions, where the front-sided transparent conductive material stack comprises a front-sided first transparent conductive layer comprising a first base material with a first doping and having a non-stoichiometric composition with a first deviation from stoichiometry, where the first base material is chosen from the group of materials including indium oxide, zinc oxide, tin oxide, and cadmium oxide, and a front-sided second transparent conductive layer or structure comprising the first base material or a second base material, the first or second base material having the first doping or a second doping being different from the first doping and having a non-stoichiometric composition, where the composition of the second base material is different from the composition of the first base material and where the composition of the first base material has a second deviation from stoichiometry being different from the first deviation from stoichiometry, respectively, where the average carrier concentration of the whole front-sided transparent conductive material stack is between 1x1020 cm-3 and 2x1020 cm-3; the refractive indices (n) of the front-sided first transparent conductive layer and of the front-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 font-sided first transparent conductive layer is higher than the carrier mobility in the front-sided second transparent conductive layer or structure if the layers/structure have a comparable thickness. An INDEPENDENT CLAIM is included for a method of manufacturing a photovoltaic device with a hetero-junction, the photovoltaic device being prepared with a front side for an incidence of light, involving providing a crystalline semiconductor body, forming a front passivation layer on the crystalline semiconductor body, forming an emitter or a front surface field layer on the front passivation layer, providing a front-sided transparent conductive material stack, and forming a front grid metallization, where the front-sided transparent conductive material stack is provided by forming a stack of at least two transparent conductive components having different compositions, comprising forming a front-sided first transparent conductive layer on the emitter, where the front-sided first transparent conductive layer is formed using a first base material with a first doping and having a non-stoichiometric composition with a first deviation from stoichiometry, and where the first base material is chosen from the group of materials including indium oxide, zinc oxide, tin oxide, and cadmium oxide, and forming a front-sided second transparent conductive layer or structure where the front-sided second transparent conductive structure is formed using the first base material or a second base material, the first or second base material having the first doping or a second doping being different from the first doping and having a non-stoichiometric composition, where the composition of the second base material is different from the composition of the first base material and where the composition of the first base material has a second deviation from stoichiometry being different from the first deviation from stoichiometry, respectively, where the average carrier concentration of the whole front-sided transparent conductive material stack is between 1x1020 cm-3 and 2x1020 cm-3; the refractive indices (n) of the front-sided first transparent conductive layer and of the front-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 front-sided first transparent conductive layer is higher than the carrier mobility in the front-sided second transparent conductive layer or structure if the layers/structure have a comparable thickness.