Oligoazomethine-doped planar tunnel junctions: Correlating molecular structure with junction electrical characteristics

Abstract

Articles you may be interested inVibrational spectra of metal-molecule-metal junctions in electromigrated nanogap electrodes by inelastic electron tunneling Appl.

Influence of Linker Molecules on Charge Transport through Self-Assembled Single-Nanoparticle Devices

“…Since long alkane chains present large barriers (6 eV [9]), locations at or near the Au-S interface again are likely possibilities [21]. The presence of small barriers at metal-molecule contacts has been reported to describe tunneling behavior of molecule-doped tunnel junctions [10]. The nonuniform molecular potential profiles are also consistent with a picture proposed by Ref.…”

“…We believe that an important source of the discrepancy may be that molecular monolayers in SEDs may not act as simple tunnel barriers. Molecules can exhibit more complex behavior [8], ranging from nonuniform voltage drops [9] as a result of multibarrier potentials [10] to interactions with molecular orbitals, which in turn can give rise to processes such as resonant tunneling and oxidation reduction [11]. To better understand such potential influences, we have studied the effects of varying V, T, and NP size on the electrical characteristics of the simplest prototypical self-assembled SED comprising alkanedithiols and Au NPs.…”

Differential Conductance Switching of Planar Tunnel Junctions Mediated by Oxidation/Reduction of Functionally Protected Ferrocene

“…At lower temperatures higher threshold voltages were observed, whereas at higher temperatures junctions tended to show more frequent irreversible differential conductance increases after only one or two voltage sweep cycles. Thus to reduce difficulties due to localized heating and to obtain better yield and reproducibility, we performed most measurements at 210 K. Generally, the differential conductance of our tunnel junctions exhibited thermally assisted behavior, as has been observed by us and others in different systems. ,32b All junctions typically exhibited 0 V differential conductance drops of ∼30% as the temperature was lowered from 298 to 211 K. The temperature dependence may arise from thermally assisted transport across metal−molecule interfacial barriers and nuclear motion. ,32b

5 Histogram of conductance switching threshold voltages observed using FDCA tunnel junctions at 210 K.

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“…[68][69][70] A lower molecular barrier increases the overall transmission and differential conductance of a tunnel junction since transmission in a WKB approximation is given by the product of the transmissions through the oxide and the molecules separately. 11 Note that a positive charge on the molecules is expected to make hole transport more difficult and lower differential conductance if holes were the dominant charge carriers. Cycling the bottom electrode to sufficiently positive potentials reduces the FDCA + back to FDCA through injection of electrons from the top electrode, lowering differential conductance again.…”

“…Planar tunnel junctions (PTJs) are a very attractive platform for investigating a wide variety of molecular electronic behaviors and for exploring their potential device applications. − PTJs are straightforward to fabricate and are cost-effective. They are scalable, potentially down to molecular levels. , They are also extremely sensitive to barrier structure, and therefore, their behavior can be tuned by doping junctions with suitably designed molecular architectures.…”