NOVELTY - The method comprises texturing (904) a topside of a substrate, where the substrate is made from a first semiconductor of single-crystal silicon and multi-crystalline silicon lightly doped with a first dopant type having a first majority carrier and has a backside, forming (906) a second semiconductor layer overlying the first semiconductor substrate topside, where the second semiconductor layer is made from hydrogenated amorphous silicon (a-Si:H) and is doped with the first dopant, and forming (908) an antireflective coating overlying the second semiconductor layer.    USE - The method is useful for fabricating an organic semiconductor heterojunction back contact solar cell.    ADVANTAGE - The method is capable of efficiently, simply and economically fabricating the solar cell with high electron mobility and improved photoconversion efficiency and without front surface reflection loss and series resistance loss.    DETAILED DESCRIPTION - The method comprises texturing (904) a topside of a substrate, where the substrate is made from a first semiconductor of single-crystal silicon and multi-crystalline silicon lightly doped with a first dopant type having a first majority carrier and has a backside, forming (906) a second semiconductor layer overlying the first semiconductor substrate topside, where the second semiconductor layer is made from hydrogenated amorphous silicon (a-Si:H) and is doped with the first dopant, forming (908) an antireflective coating overlying the second semiconductor layer, forming (910) a third semiconductor layer overlying the first semiconductor substrate backside, where the third semiconductor layer is made from intrinsic a-Si:H, forming (912) a first majority carrier type organic semiconductor layer overlying the third semiconductor layer in a first pattern, forming a second majority carrier type organic semiconductor layer overlying the third semiconductor layer in a second pattern, forming spaces between the first and second majority carrier type organic semiconductor layers, forming a dielectric organic semiconductor layer overlying the first and second majority carrier type organic semiconductor layers using screen printing and inkjet printing process, filling the spaces with openings exposing the first and second majority carrier type organic semiconductor layers that respectively form first and second organic semiconductor contact regions, depositing lithium fluoride overlying the first and second organic semiconductor contact regions, and forming a first metal grid and a second metal grid connected to first and second organic semiconductor contact regions respectively using a deposition process consisting of vacuum deposition, screen printing and inkjet printing. The first and second patterns include channels in the first and second majority carrier type organic semiconductor layers that expose the third semiconductor layer. The second majority carrier is opposite in polarity to the first majority carrier. The second pattern of second majority carrier type organic semiconductor incompletely fills the channels in the first majority carrier type organic semiconductor. The first semiconductor substrate has a thickness of 2-400 microns with a first dopant density of 5x 1014 to 1x 1016 cm-3. The steps of forming the first and second majority carrier type organic semiconductor layers are performed by a process consisting of screen printing and inkjet printing to deposit the first and second patterns as a sequence of stripes respectively. The step of forming the first majority carrier type organic semiconductor layer includes depositing an n-type organic semiconductor. The step of forming the second majority carrier type organic semiconductor layers includes depositing a p-type organic semiconductor. Each first and second organic semiconductor layers has a charge carrier density of 5x 1018 to 5x 1020 cm-3, and a resistivity of 1x 10-3 to 10 ohm-cm. An INDEPENDENT CLAIM is included for an organic semiconductor heterojunction back contact solar cell.    DESCRIPTION OF DRAWING(S) - The diagram shows a flow chart of a method for fabricating a solar cell.    Providing a substrate (902)    Texturing a topside of the substrate (904)    Forming a second semiconductor layer (906)    Forming antireflective coating (908)    Forming a third semiconductor layer (910)    Forming first majority carrier type organic semiconductor in first pattern. (912)