Electron transport properties of ZnO, InP, GaP, and Pb1-xMnxSe nanowires by two-probe measurements

Nanowires (NWs) of four different materials, including ZnO, InP, GaP, and Pb_1-xMn_xSe, have been used for the fabrication of two-probe electronic devices to study electrical transport properties. The average diameters of ZnO, InP, GaP, and Pb_1-xMn_xSe NWs are about 40, 25, 25, 70 nm, respectively. Both electron-beam lithography and dielectrophoresis techniques are employed to either deposit two Ti/Au electrodes on single NW or positioned the NW into nanometer gap between two electrodes. Temperature dependent behaviors of resistance of two-probe devices are measured to explore the electron transport either in the NW or in the nanocontact formed in the interface between the NW and the Ti/Au electrodes. Two-probe devices with high and low room-temperature resistance are used to inspect and distinguish the interplay between the nanocontact and the NW. After the separation of NW-dominated devices from contact-dominated ones, the thermally activated transport in semiconductor ZnO, InP, and GaP NWs and the temperature independent tunneling conduction in Pb_1-xMn_xSe NWs have been revealed. On the other hand, the contact-dominated devices display electron hopping transport in the nanocontact. Moreover, the fluctuation-induced tunneling conduction in the overlapped Pb_1-xMn_xSe NWs has been observed.