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Aluminium (Al)-doped zinc-oxide (ZnO) nanorod arrays have been successfully prepared using a novel and low-temperature sonicated sol–gel immersion method. The photoluminescence (PL) spectrum reveals the appearance of two emission peaks from the nanorod that are centred at 381 and 590 nm. The nanorod has a hexagonal structure with a flat-end facet, as observed using field-emission electron microscopy (FESEM). Interestingly, all samples have similar surface morphologies and diameter sizes of 40 to 150 nm after immersion in different precursor-solution volumes. The thickness-measurement results show that the thicknesses of the samples increase after immersion in higher precursor-solution volumes. We show for the first time that the growth of nanorod arrays along the c-axis can be controlled using different precursor volumes, and its growth mechanism is discussed. X-ray diffraction (XRD) spectra indicate that the prepared nanorods are ZnO with a hexagonal wurtzite structure that grows preferentially along the c-axis.

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Carbon nanotubes (CNTs) were fabricated from palm oil using the thermal chemical vapor deposition technique utilizing a two furnace system. The effect of precursor vaporization temperature of the first furnace, in the range of 300-600°C was systematically studied with the synthesis temperature (second furnace) fixed at 750°C for a total time of 30 min. The samples were characterized using field emission scanning electron microscopy and micro-Raman spectroscopy. CNTs of various packing densities and diameters were synthesized with the varying precursor vaporization temperature. Based on micro-Raman measurements nanotube defect level and the presence of SWCNT were dependent on the vaporization temperature. Vertically aligned CNTs (VACNTs) were found to grow within the vaporization temperature range of 400-500°C, with well graphitized and higher yield obtained at 450°C with excellent lateral alignment, uniform nanotubes diameter (~15 nm), orientation and distribution within the CNT bundles. At vaporization temperatures of 300-350°C and 500-600°C, lower growth rate, bigger nanotubes diameter and higher ID/IG ratio were observed which indicated lower nanotubes quality that produced at both temperature ranges.