NOVELTY - A solar cell comprises a semiconductor wafer (100), a first semiconductor layer (200), a first transparent conductive layer (400), a first electrode (500), a second semiconductor layer (600), a second transparent conductive layer (800), a second electrode (900), and a first auxiliary layer (300) and a second auxiliary layer (700). The auxiliary layers improve drift of carriers from the wafer to the second transparent conductive layer.    USE - A solar cell.    ADVANTAGE - The solar cell improves cell efficiency by smoothly drifting carrier such as hole or electron generated in a semiconductor wafer to first and second electrodes.    DETAILED DESCRIPTION - A solar cell comprises:    (A) a semiconductor wafer (100) having a first polarity;    (B) a first semiconductor layer (200) on a first surface of the wafer;    (C) a first transparent conductive layer (400) on the first semiconductor layer;    (D) a first electrode (500) on the first transparent conductive layer;    (E) a second semiconductor layer (600) on a second surface of the wafer opposite to the first surface, and having a second polarity different from the first polarity;    (F) a second transparent conductive layer (800) on the second semiconductor layer;    (G) a second electrode (900) on the second transparent conductive layer; and    (H) a first auxiliary layer (300) and a second auxiliary layer (700), where the first auxiliary layer is between the first semiconductor layer and the first transparent conductive layer and improves drift of carriers from the wafer to the first transparent conductive layer, and the second auxiliary layer is between the second semiconductor layer and the second transparent conductive layer, the auxiliary layer being adapted to improve drift of carriers from the wafer to the second transparent conductive layer.    The first auxiliary layer comprises a negative polarity material layer to attract holes from the wafer, and the second auxiliary layer comprises a positive polarity material layer to attract electrons from the wafer. The first semiconductor layer comprises a P-type semiconductor layer, and the second semiconductor layer comprises an N-type semiconductor layer. The first and second semiconductor layers comprise a lightly-doped semiconductor layer (210, 610) on the wafer, and a highly-doped semiconductor layer (220, 620) on the lightly-doped semiconductor layer. An INDEPENDENT CLAIM is included for manufacturing the solar cell.    DESCRIPTION OF DRAWING(S) - The drawing is a cross-sectional view of the solar cell.    Semiconductor wafer (100)    First semiconductor layer (200)    Lightly-doped semiconductor layer (210, 610)    Highly-doped semiconductor layer (220, 620)    First auxiliary layer (300)    First transparent conductive layer (400)    First electrode (500)    Second semiconductor layer (600)    Second auxiliary layer (700)    Second transparent conductive layer (800)    Second electrode (900)