A photosensitive thin film device includes a substrate that is transparent and insulative; a first electrode on the substrate; a circular semiconductor layer on the substrate and surrounding a perimeter of the first electrode; a circular second electrode on the substrate and surrounding a perimeter of the semiconductor layer; an interlayer insulating layer on the semiconductor layer and the first and second electrodes and having a first aperture exposing the first electrode; and a conductive layer including an upper surface light barrier arranged on the interlayer insulating layer and covering an upper surface of the semiconductor layer, and a contact plug extending from the upper surface light barrier and connected to the first electrode via the first aperture.