NOVELTY - A photovoltaic device (100) comprises substrate (112), supporting layer or light transmissive superstrate; light transmissive electrode located above superstrate; reflective electrode located above light transmissive electrode; semiconductor layer stack (116) between reflective electrode and light transmissive electrode; and optical spacer layer between reflective electrode and semiconductor layer stack. The optical spacer layer includes conductive and light transmissive material. The semiconductor layer stack has first and second sublayers.    USE - Photovoltaic device for production of solar panels.    ADVANTAGE - The device is manufactured more quickly and at a lower cost, while increasing levels of crystallinity in semiconductor layers and maintaining dopant junctions within semiconductor layers. The device also enables production of lower cost solar panels of larger surface area, with higher stability and higher efficiency than many existing solar panels; and converts incident light into electricity at module efficiency of at least approximately 8%.    DETAILED DESCRIPTION - The photovoltaic device (100) comprises substrate (112), supporting layer or light transmissive superstrate; light transmissive electrode located above superstrate; reflective electrode located above light transmissive electrode; semiconductor layer stack (116) between reflective electrode and light transmissive electrode; and optical spacer layer between reflective electrode and semiconductor layer stack. The optical spacer layer includes conductive and light transmissive material. The semiconductor layer stack has first and second sublayers. The second sublayer comprises polycrystalline semiconductor material having crystalline fraction of at least approximately 85% An INDEPENDENT CLAIM is included for a method for manufacturing the photovoltaic device comprising providing light transmissive superstrate; depositing light transmissive electrode above superstrate; depositing semiconductor layer stack above light transmissive electrode; increasing level of crystallinity in second sublayer; depositing optical spacer layer above semiconductor layer stack; depositing reflective electrode above optical spacer layer.    DESCRIPTION OF DRAWING(S) - The drawing is a perspective view illustrating a photovoltaic device.    Photovoltaic device (100)    Substrate (112)    Bottom electrode (114)    Semiconductor layer stack (116)    Top electrode (118)