Session V16: Nanowires: Electrical and Thermal Properties

8:00 AM–11:00 AM, Thursday, March 18, 2010
Room: B115

Sponsoring Unit: DCMP
Chair: Derek Stewart, Cornell University

Abstract ID: BAPS.2010.MAR.V16.13

Abstract: V16.00013 : Temperature- and time-dependence of hot-electron injection and accumulation in vertical Si nanowires studied with nm-resolution ballistic electron emission microscopy

10:24 AM–10:36 AM

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Authors:

  J.P. Pelz
    (The Ohio State Univ.)

  W. Cai
    (The Ohio State Univ.)

  Y. Che
    (The Ohio State Univ.)

  E.R. Hemesath
    (Northwestern Univ.)

  L.J. Lauhon
    (Northwestern Univ.)

Semiconducting nanowires (NWs) are of great interest for new devices, but the influence of quantum and geometry-related size effects on NW carrier injection and transport must be better understood. We report ballistic electron emission microscopy (BEEM) measurements of hot-electron injection into individual ``end-on'' metal Schottky contacts to vertical Si-NWs at 80-300K. We observe increasing \textit{suppression} of BEEM current with increasing hot-electron flux compared to a regular Au/Si junction, which we propose to be due to a \textit{steady-state (SS) charge accumulation} in the NW that increases with the amplitude of injected current. The suppression varies greatly for different NWs (suggesting an extrinsic defect-related mechanism) and increases strongly at lower temperature, likely due to increased SS charge accumulation. Dynamic charge trapping or de-trapping behavior (with time scale in the range of 50 to 200 ms) is observed when the tunnel current is abruptly changed, supporting that the suppression is due to (temperature-dependent) SS charge accumulation. Electrostatic simulations of carrier trapping at the Si/SiO$_{2}$ interface at NW walls [1] are consistent with the observed suppression. Work supported by NSF Grant No. DMR-0805237. \\[4pt] [1] Y. Cui \textit{et al}., Nano Lett. \textbf{3}, 149 (2003).

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.MAR.V16.13