Abstract
The present invention provides a solar cell fabricated with a single-crystalline, polycrystalline or amorphous semiconductor wafer. The semiconductor wafer has etched holes or a groove array on it. The depths of the holes or grooves are larger than one fourth thickness of the wafer. Or, the bottom areas of the holes or grooves are within 50 micrometers to the opposite side of the wafer. Without forming a buried contact structure, the present invention shortens diffusion distance of carriers, and thus enhances opto-electric conversion efficiency.