%0 Journal Article
%T Symmetric Negative Differential Resistance in a Molecular Nanosilver Chain
%A Tae Kyung Kim
%A Hoi Ri Moon
%A Byung Hoon Kim
%J Journal of Nanomaterials
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/814694
%X The electrical transport properties of the molecular nanosilver chain have been investigated. We observed the symmetric negative differential resistance (NDR) in the current-voltage characteristics. The peak voltage ( ) increased but the peak current ( ) decreased upon cooling. The self-capacitance effect of the silver chain crystal is suggested to explain this unconventional NDR phenomenon. 1. Introduction Negative differential resistance (NDR) has attracted much interest due to its applications for switch, memory, and high-speed logic devices. NDR explained by a resonance tunneling diode has been shown in various materials, such as germanium p-n junction [1], various heterostructures [2¨C6], semiconductor superlattices [7], self-assembled layered nanostructures [8], carbon atomic wires [9], mesoscopic manganite structures [10], and molecular electronics device systems [11¨C13]. The NDR has also been observed in grapheme nanoribbon with unsaturated edges due to the strong current polarization [14] and due to the interaction between the narrow density of state of doped sites and the discrete states in the scattering region [15]. In addition, Ag-based materials, such as Ag/Si nanowires on silicon carbide, exhibited NDR as well [16]. NDR phenomena in general, including those mentioned above, exhibited asymmetric current-voltage ( - ) characteristics with respect to the applied voltage. Recently, Moon et al. reported a stair-shaped Ag0 coordination compound without bridging ligands (nanosilver chain) [17]. This nanosilver chain (NSC) consists of Ag atoms linked by covalent bonds and pyridine molecules. Herein, we report the abnormal -shaped NDR phenomenon of the single crystalline NSC and temperature-dependent NDR behavior that cannot be interpreted by previously reported mechanisms. The - characteristics in the backward voltage sweep were symmetric to that in the forward voltage sweep. Hysteretic behavior was manifested as well. The peak voltage ( ) increased and the peak current ( ) decreased as the temperature decreased. We suggest that the NDR phenomenon of the NSC may be caused by a capacitance effect of the NSC itself. 2. Materials and Methods The - characteristics were measured with the conventional 2-probe method. Silver paint (DuPont 4929N) and carbon paint (Dotite XC-12) contacts were made to 0.01 inch diameter gold wires. The - characteristics were doubly checked using semiconductor characterization systems (Keithley 4200-SCS) and electrometer (Keithley 6517A). The voltage sweep rate was 10£¿mV/sec. The temperature-dependent - characteristics were
%U http://www.hindawi.com/journals/jnm/2013/814694/