We fabricated the solar cell structure of n(++)-type poly silicon/non-doped oxygen-containing silicon quantum dots superlattice (Si-QDSL)/p-type hydrogenated amorphous silicon/aluminum electrode on a quartz substrate and successfully improved the electrical characteristics in the Si-QDSL solar cells which include 5 nm silicon quantum dots embedded in hydrogenated amorphous silicon carbide (a-SiC:H). This improvement was achieved by the introduction of oxygen into the Si-QDSL layer and the reduction of the sheet resistance in the n(++)-type poly-silicon layer. The open-circuit voltage and fill factor of 518 mV and 0.51 were obtained, respectively. At least this result indicates that the quality of the O-containing Si-QDSL (Si-QDSL:O) layer was improved electrically. Therefore, it is suggested that part of the observed photocurrent generated in the Si-QDSL:O layer.