SEMICONDUCTOR-TINI JUNCTION ELECTRONIC DEVICE

AT THE JUNCTION OF A SEMICONDUCTOR AND A METAL, THE INITIAL MISMATCH IN CHEMICAL POTENTIALS OF THE TWO MATERIALS LEADS TO AN ELECTRIC FIELD IN THE SEMICONDUCTOR AS A CHARGE CROSSES THE INTERFACE TO EQUALIZE THESE POTENTIALS. THE RESULTING ELECTRIC FIELD OR DEPLETION WIDTH AFFECTS THE PHOTOLUMINESCENCE BEHAVIOR IN THE SEMICONDUCTOR BECAUSE ELECTRON-HOLE PAIRS THAT ARE GENERATED IN THIS ZONE ARE SEPARATED BY THE FIELD AND THUS CANNOT RADIATIVELY RECOMBINE. IT IS PLANNED TO EXPLORE THIS PHENOMENON AS A PROBE OF THE ELECTRONIC STRUCTURE OF TITANIUM-NICKEL (TINI) THIN FILM. TINI SHAPE-MEMORY ALLOY UNDERGOES A SOLID-STATE PHASE CHANGETHAT IS EXPECTED TO ALTER THE FERMI LEVELS IN THE UNDERLYINGSEMICONDUCTOR. THERE IS A POSSIBILITY OF DEVELOPING A TRANSDUCER THAT IS SENSITIVE TO THE CRYSTALLINE STATE OF TINI AND MAY BE A SENSITIVE MINIATURE CHEMICAL PROBE. FILMS OF TINI SHAPE-MEMORY ALLOY WILL BE PREPARED IN THICKNESSES VARYING FROM A FEW THOUSAND ANGSTROMS TO SEVERAL MICRONS, SPUTTERED ONTO A VARIETY OF SUBSTRATES. THESE TEST SAMPLES WILL BE STUDIED BY PHOTOLUMINESCENCE AS THE TEMPERATURE IS VARIED THROUGH THE TRANSITION TEMPERATURE OF THE TINI FILM. THE EXPECTED RESULT IS A SIGNIFICANT SHIFT IN THE SPECTRUM AND/OR INTENSITY OF EMITTED LIGHT WHEN THE PHASE CHANGE OCCURS.