Nanodiode

H.G. Kim, P.H. Borse, W. Choi, J.S. Lee, Photocatalytic nanodiodes for visible light photocatalysis, Angew. Chem. Int. 

J. Veinot, H. Yan, S. Smith, J. Cui, Q. Huang, and T.J. Mark Fabrication and Properties of Organic Light-Emitting Nanodiode Arrays. Nano Lett. 2,333 (2002). Y. Xia, B. Gates, and Z.-Y. Li Self-Assembly Approaches to Three-Dimensional Photonic Crystals. Adv. Mater. 13, 409 (2001). 

Other applications of single CPNWs include nanodiodes and nanoactuators. For example, a single Au-PPY-Cd-Au nanowire could be formed as a nanodiode after a Schottky junction was formed at the PPY/Cd interface and an ohmic junction was formed at the PPY/Au interface (Figure 10.58) [47]. An array of parallel PP Y nanowires was used as a nanoactuator as the mechanical function was derived from the expansion and contraction of the PPY nanowires caused by the movement of ions into and out of the polymer matrix in an aqueous eletrolyte during electrically controlled reversible reduction and oxidation [122]. 

Sailor and Martin and coworkers grew an array of CdSe-CdTe nanodiodes [144]... 

CaFe204 interfaced over a highly crystalline layered perovskite base lattice (n-type PbBi2Nb1.9W0.1O9) was reported to act as photocatalytic nanodiodes for visible-light photocatalysis [97]. 

Fig. 1.2 Schematic showing the evolution of the catalyst model system from a single crystal metal surface to 2D and 3D nanoparticle arrays that are colloid synthesized and to nanowire arrays and nanodiodes that are fabricated using lithography. (Adapted from ref [5], reprinted with permission)...

Fig. 1.13 (left) Scheme of catalytic nanodiodes and (right) energy diagram of catalytic nanodiodes... 

Hervier A, Renzas JR, Park JY, Somorjai GA (2009) Hydrogen oxidation-driven hot electron flow detected by catalytic nanodiodes. Nano Lett 9 3930-3933. doi 10.1021/nl9023275 Nienhaus H (2002) Electronic excitations by chemical reactions on metal surfaces. Surf Sd Rep 45 3-78... 

Park JY, Somorjai GA (2006) The catalytic nanodiode detecting continuous electron flow at oxide-metal interfaces generated by a gas-phase exothermic reaction. Chemphyschem 7 1409-1413... 

Lee YK et al (2011) Surface plasmon-driven hot electron flow probed with metal-semiconductor nanodiodes. Nano Lett 11 4251 255. doi 10.1021/nl2022459... 

Nienhaus et al. were the first to successfully measure chemicurrent on a nanodiode [3, 50]. Their devices consisted of Ag and Cu thin films deposited onto n- and p-doped Si wafers, with ohmic contacts on both sides of the wafer. When these diodes were exposed to a beam of H atoms, a current on the order of 0.01-1 nA was... 

The electronic effect involves charge transfer between the metal and the oxide support. Elucidation of the origin of the metal-support interaction requires measurement of the charge transfer through the oxide-metal interface. To detect this charge transfer (or flow of hot electrons) under catalytic reaction conditions, metal-semiconductor Schottky diodes have been developed [3, 62]. In this section, we will outline recent research on catalytic nanodiodes. The detection of hot electrons under various catalytic reactions and the influence of hot electrons in catalytic reactivity will also be discussed in this section. 

Fig. 10.5 (a) Scheme and (b) energy diagram of catalytic nanodiodes. Hot electrons can be generated by exothermic catalytic reactions... 

Fig. 10.6 Scheme of Pt/Ti02 and Pt/GaN nanodiodes. (Reprinted with permission from ref. [70]. 2007 American Chemical Society.)... 

To determine barrier heights and ideality factors for the nanodiodes, we fit the current-voltage curves of our devices to the thermionic emission equation. For thermionic emission over the barrier, the current density of Schottky contacts as a function of applied voltage is given by [69]. 

Hot Electron Flows Detected on Catalytic Nanodiodes Under Exothermic Catalytic Reaction... 

Pig. 10.13 Future directions of hot electron studies, including (a) development of hybrid nanoparticle-nanodiode systems, and (b) in situ surface characterization. The cartoon depicts the conductive atomic force microscopy experiments on Au/liOj nanostructures under exothermic catalytic reactions or photon irradiation... 

Park JY, Renzas JR, Hsu BB, Somorjai GA (2007) Interfacial and chemical properties of Pt/ TiOj, Pd/liOi, and Pt/GaN catalytic nanodiodes influencing hot electron flow. J Phys Chem C 111 15331-15336... 

Park JY, Somorjai GA (2006) Energy conversion from catalyic reaction to hot electron ctrr-rent with metal-semiconductor Schottky nanodiodes. J Vac Sci Technol B 24 1967-1971... 

Ji XZ, Zuppero A, Gidwani JM, Somorjai GA (2005) Electron flow generated by gas phase exothermic catalytic reactions using a platinum-gallium nitride nanodiode. J Am Chem Soc 127 5792-5793... 

Lee YK, Lee J, Lee H, Lee JY, Park JY (2013) Probing polarization modes of Ag nanowires with hot electron detection on Au/TiOj nanodiodes. Appl Phys Lett 102 123112... 

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