Synthesis of Metallic Iridium Oxide Nanowires via Metal Organic Chemical Vapor Deposition

Abstract

Iridium oxide (IrO2) nanowires with diameters of 10 to 50 nm and length of 1 to 2 microns were synthesized using Metal Organic Chemical Vapor Deposition (MOCVD) with (methylcyclopentadienyl) (1,5-cyclooctadiene) iridium (I) as the precursor on Si or SiO2 substrate with and without metal nanoparticles as catalysts. Scanning electron microscopy (SEM) and low-resolution transmission electron microscopy (LRTEM) studies show very uniform nanowires diameters and high-resolution (HR) TEM image and electron diffraction pattern reveal single crystal IrO2 nanowires having rutile structure with the growth direction along <001>. HRTEM studies further indicate that the IrO2 nanowires were grown via vapor-solid mechanism having naturally formed sharp tips. It was found that a thin layer of metal film on Si substrate, such as Au, Ti, Ni, and Co, facilitate IrO2 nanowires synthesis and selective growth of IrO2 nanowires on substrate was realized. The IrO2 nanowires are metallic conductive using titanium as contact without annealing. The ability to grow single crystal metallic IrO2 nanowires opens up novel opportunities in vacuum electronics, nanoelectronics, field emission and display applications.