Electrical transport studies of individual IrO₂nanorods and their nanorod contacts

Abstract

We have studied the electrical transport properties of individual single-crystalline IrO(2) nanorods prepared by the metal-organic chemical vapour deposition method. With the help of the standard electron-beam lithographic technique, individual nanorods are contacted by Cr/Au submicron electrodes from above. Utilizing two-probe, three-probe and four-probe measurement configurations, not only the intrinsic electrical transport properties of the individual nanorods but also the electronic contact resistances, R(c)(T), have been determined from 300 K down to liquid-helium temperatures. Our measured resistivity behaviour of the nanorods is in close agreement with the current theoretical understanding of this rutile material. On the other hand, we found that the temperature behaviour of the electronic contact resistance obeys the law [Formula: see text] over an extremely wide temperature range, from approximately 100 K down to liquid-helium temperatures. This latter conduction process is ascribed to the hopping of electrons through nanoscale Cr granules and/or an amorphous coating incidentally formed at the interface between the submicron Cr/Au electrode and the nanorod.

Metallic conduction and large electron-phonon-impurity interference effect in single TiSi nanowires

“…Our fitted values of ${\beta }_{\mathrm{normali}\mathrm{nt}}\sim 10^{-6}$−1 0−5 K −2 are in similar orders of magnitude with those previously obtained in normal metals, such as Au [8], Al [9], and AuPd [11]. What is more interesting is that previous studies of a variety of metals have found that the EPI interference effect was important only at considerably low temperatures [8-12]. In sharp contrast, we find that in our TiSi NWs, ρ int ( T ) can largely dominate over ρ BG ( T ) even up to temperatures as high as room temperature.…”

“…This unique property renders the TiSi NWs useful for the investigations of the interplay among a variety of electron-scattering processes at the nanoscale level. Previously, the EPI interference effect has been found to be important in normal metals only at considerably lower temperatures [8-12]. …”

Time-dependent universal conductance fluctuations in IrO2 nanowires

“…The morphology and atomic structure of the nanowires were studied by scanning electron microscopy (SEM) and transmission electron microscopy. Four-probe single nanowire devices were fabricated by the electron-beam lithography, as described previously [22]. (The inset of Figure 1 shows an SEM image of the NW1 device taken from [22].…”

“…Four-probe single nanowire devices were fabricated by the electron-beam lithography, as described previously [22]. (The inset of Figure 1 shows an SEM image of the NW1 device taken from [22]. In [22], the electrical transport properties of the two NW1 and NW2 nanowire devices had been studied at high temperatures of 30 to 300 K.) The resistance measurements were performed on a standard 4 He cryostat.…”

“…(The inset of Figure 1 shows an SEM image of the NW1 device taken from [22]. In [22], the electrical transport properties of the two NW1 and NW2 nanowire devices had been studied at high temperatures of 30 to 300 K.) The resistance measurements were performed on a standard 4 He cryostat. A Linear Research LR-700 ac resistance bridge (Linear Research Inc., San Diego, CA, USA) operating at a frequency of 16 Hz was employed for resistance measurements.…”