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Electrical properties of silver selenide (Ag 2 Se) thin film, which is a thickness of 500 nm, were studied using conducting atomic force microscopy (c-AFM). A resistive switching was observed in the sweep voltage range from −7 to +7 V at room temperature. In addition, the Ag/Ag 2 Se/Au structure was compared with the Ag 2 Se/Au structure. It was considered that the resistive switching behavior may cause Ag filaments. The typical resistive characteristics of the Ag 2 Se thin film were presented, and the mechanism was discussed.

Reportedly, molecular wires which have intrinsically different characteristics from semiconductor nano wires show some unique transport properties. However, it seems that there is not so much understanding about their local properties. So, in this work, we characterized electrical properties of carotenoid which had differently substituted end-groups by using Scanning Probe Microscopy. To confirm the difference of the electrochemistry with substituted end-groups, we performed cyclic voltammetry in au aqueous solution. Electrochemical reaction was detected in the potential region between 0.5 and 0.75 V vs. Ag rceil AgCI rceil KCl (sat), whereas the conductance values were showed difference of differently substituted end-groups. Physisorptional effect between molecule and Au substrate was removed by introducing thiol[SH] group at each end of molecule resulting in covalent bond. After inserting these molecules into a 1-methylsulfanyl-octadecane monolayer pre-deposited on Au substrate, an Au nanoparticle is attached to the other end of each molecule via the protruding thiol group. To confirm the chemical conjunction between au Au nanoparticle and carotenedithiol molecule, we performed Electrostatic Force. These measurements allow us to simulate the transport property of carotenoid molecule. Followed IN measurement reconfirmed the results.A PtIr coated AFM probe is used as an electrode to contact the molecule through the Au nanoparticle. They reveal that methoxy-phenyl substituted carotenedithiol molecules showed better conducting properties and bromo-phenyl substituted carotenedithiol molecules showed worse than phenyl-substituted one did. I also obtained that current-voltage (I-V) curves were quantized as integer multiples of one fundamental curve. These allow us to simulate the transport property of single carotenoid molecule.

Using an AFM with a conducting cantilever, the current versus voltage (I-V) characteristics of carotenedithiol molecular wires which have different end groups are measured. An Au nanoparticle is attached to each molecule via the protruding thiol group and a PtIr coated AFM probe is used as an electrode to contact with the molecule through the Au nanoparticle. Then it was reconfirmed by the I-V measurement. The results show that phenyl substituted carotenedithiol molecules are better conducting properties than those of bromo-phenyl substituted one which caused by the different electron transport properties. In this talk, we'll present the possibility of organic molecular wires for the nano devices[3].