NOVELTY - A thin-film solar cell comprises a transparent electrode layer, a semiconductor photovoltaic conversion layer, a rear transparent electrode layer, and a rear reflective metal layer, on a substrate. The rear transparent electrode has a two-layer structure of an indium tin oxide or zinc oxide:gallium layer and zinc oxide:aluminum layer on semiconductor photovoltaic conversion layer.    USE - Used for providing a clean energy alternative to nuclear energy and fossil energy.    ADVANTAGE - The thin-film solar cell has a rear transparent electrode layer that can be manufactured by a high-throughput production and exhibits a stable film quality and a good ohmic contact, improving the output characteristic, and the photovoltaic conversion efficiency even of a thin-film solar cell with a large area.    DETAILED DESCRIPTION - A thin-film solar cell comprises a transparent electrode layer, a semiconductor photovoltaic conversion layer (3), a rear transparent electrode layer (4), and a rear reflective metal layer, on a substrate (1). The rear transparent electrode has a two-layer structure of an indium tin oxide or zinc oxide:gallium layer (4a) and zinc oxide:aluminum layer (4b) formed in this order on the semiconductor photovoltaic conversion layer.    An INDEPENDENT CLAIM is included for a method for manufacturing a thin-film solar cell comprising forming a transparent electrode layer, a semiconductor photovoltaic conversion layer, a rear transparent electrode layer, and a rear reflective metal layer in this order on a transparent substrate. The rear transparent electrode layer is formed in a two-layer structure of an indium tin oxide or zinc oxide:gallium layer and a zinc oxide:aluminum layer which are continuously formed using a magnetron sputtering apparatus of a substrate-moving type having an indium tin oxide or zinc oxide:gallium target and a zinc oxide:aluminum target arranged in this order in a substrate-moving direction.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic sectional view of a thick-film solar cell.    Transparent substrate (1)    Tin oxide layer (2)    Semiconductor photovoltaic conversion layer (3)    p-Layer (3p)    i-Layer (3i)    n-Layer (3n)    Rear transparent electrode layer (4)    Indium tin oxide or zinc oxide:gallium layer (4a)    Zinc oxide:aluminum layer (4b)