Quantum Nanocrystal Sensor

RECENT OBSERVATION OF LIGHT EMISSION FROM MATERIALS CONTAINING SILICON NANOPARTICLES (INCLUDING POROUS SILICON) HAS DEMONSTRATED THAT THE OPTICAL PROPERTIES OF SILICON CAN BE DRASTICALLY ALTERED BY QUANTUM SIZE EFFECTS. IN RECENT WORK AIMED AT THE DEVELOPMENT OF LIGHT EMITTING DEVICES IN SUCH MATERIAL SYSTEMS, WE HAVE DEMONSTRATED PHOTOLUMINESCENCE RANGING FROM IR, THROUGH THE VISIBLE, TO UV, AS WELL AS THE NARROWEST PL EMISSION THAT HAS SO FAR BENN OBSERVED IN ANY Si BASED MATERIAL, INCLUDING POROUS SILICON. OUR MATERIAL CONSISTS OF Si AND Ge QUANTUM NANOCRYSTALS (QNCs) EMBEDDED IN A SILICON DIOXIDE (SiO2) MATRIX AND IS MUCH MORE RUGGED, CHEMICALLY INERT AND COMPATIBLE WITH IC PROCESSING THAN POROUS SILICON. THE Si/Ge QNC FILMS WERE FORMED BY ANNEALING SILICON DIOXIDE CONTAINING EXCESS Si OR Ge AND TEM AND RAMAN SPECTROSCOPY REVEALED THE PRESENCE OF CRYSTALLITES IN THE QUANTUM SIZE RANGE. WE NOW PROPOSE TO DEVELOP DETECTORS BASED ON THESE FILMS AS WELL AS RADIATION ABSORPTION LAYERS FOR STEALTH AND SHIELDING APPLICATIONS. SINCE THE BANDGAP OF THE SILICON NANOPARTICLES, AND THEREFORE THEIR ABSORPTION PROPERTIES CAN BE ADJUSTED BY CHANGING THE PARTICLE SIZE, THESE FILMS ARE IDEALLY SUITED FOR SOLAR CELLS, RADIATION DETECTION OR "STEALTH" TYPE APPLICATIONS. IN PHASE I, WE WILL FABRICATE MIS PHOTODETECTORS AND DETERMINE THE RELATIONSHIP BETWEEN THE QNC SIZE AND ABSORPTION COEFFICIENT.