Porous Polycrystalline Silicon Solar Cells

IT HAS BEEN SHOWN THAT EFFICIENT PHOTOLUMINESCENCE CAN BE OBSERVED FROM POROUS SILICON, WHEN THE POROSITY IS SUFFICIENTLY HIGH. THIS RESULT HAS BEEN ATTRIBUTED TO QUANTUM SIZE EFFECTS, DUE TO THE FORMATION OF SILICON "WIRES". IN RECENT WORK AIMED AT THE DEVELOPMENT OF LIGHT EMITTING DEVICES, WE HAVE ALSO DEMONSTRATED PHOTOLUMINESCENCE RANGING FROM IR, THROUGH THE VISIBLE, TO UV, IN Si AND Ge QUANTUM NANOCRYSTALS (QNCs) EMBEDDED IN A SILICON DIOXIDE (SiO(2)) MATRIX. WE NOW PROPOSE TO DEVELOP POROUS SILICON SOLAR CELLS BASED ON THE RECENT RESULTS AND OUR KNOWLEDGE OF NANOSTRUCTURED MATERIALS. THESE SOLAR CELLS WILL BE FABRICATED BY A UNIQUE WAFER BONDING PROCESS AND ALSO BY MODIFYING EXISTING COMMERCIAL SOLAR CELLS. THE BAND STRUCTURE OF POROUS SILICON IS IDEALLY SUITED FOR SOLAR CELL APPLICATIONS. THIS IS SUPPORTED BY THE RECENT DEMONSTRATION OF A HIGHLY SENSITIVE PHOTODETECTOR, WITH CLOSE TO UNITY QUANTUM EFFICIENCY.