Specific surface effect on transport properties of NiO/MgO heterostructured nanowires

NiO heterostructured nanowires are promising building blocks due to the nonvolatile resistive switching in nanoscale. Here, we report on the noncontact transport measurements of single crystalline NiO/MgO heterostructured nanowires by utilizing a microwave conductivity method. We found the substantial discrepancy up to four orders of magnitude between the heterostructured nanowires and heterothin films on the resistivity when the bulk resistivity increased, whereas the reasonable agreement was found for relatively conductive range. The origin of such huge discrepancy was interpreted in terms of both the large specific surface area of nanowires and the surface transport events of insulative NiO. (C) 2009 American Institute of Physics. [doi:10.1063/1.3237176]