Solar cell

A solar cell, comprising:

• a substrate of a first conductive type having a plurality of via holes, the plurality of via holes penetrating the substrate;
• an emitter layer of a second conductive type opposite to the first conductive type;
• and
• a plurality of first electrodes positioned from a first surface of the substrate to the plurality of via holes and being in contact with the emitter layer;
• and
• a plurality of first electrode current collectors positioned from the plurality of via holes to a second surface of the substrate opposite the first surface,
• wherein the plurality of via holes are positioned on a portion of the substrate on which the plurality of first electrodes and the plurality of first electrode current collectors cross and at least one of the plurality of first electrodes and at least one of the plurality of first electrode current collectors are positioned in at least one via hole of the plurality of via holes, and
• wherein two cavities that are depressed into the plurality of via holes are positioned at crossed portions of the plurality of first electrodes and the plurality of via holes or at crossed portions of the plurality of first electrode current collectors and the plurality of via holes, and the two cavities have different diameters from each other.