Synthesis of metal oxide nanowall structures using a carbon nanowall template

We report a synthetic technique for the preparation of -Fe2O3 nanowall (NW) structures using carbon nanowalls (CNWs) as templates. The insertion of Fe atoms inside the CNWs is achieved by the simultaneous sputtering of the Fe target during CNW growth by plasma-enhanced chemical vapor deposition. By annealing of Fe-inserted CNWs at 500 °C-700 °C in air, the C is oxidized and desorbs as CO2, during which the Fe is sintered and NW structures are maintained. Consequently, the desired -Fe2O3 NWs are obtained. SEM observation reveals that the -Fe2O3 NW consisted of nanoparticle chains with diameters of approximately 40 to 50 nm upon increasing the annealing temperature from 500 °C to 700 °C. SiO2 ( -quartz) NWs are also formed using similar processes through the appropriate choice of sputtering target. These results demonstrate the possibility of controlling the composing atom of oxide NW structures using universal processes and conditions.