The synthesis of silicon nanotube (SiNT) has been demonstrated by various groups, each using different growth process. The synthesis of SiNTs by chemical vapor deposition was reported. The tubes were grown on alumina nanochannel arrays using gold particles as catalysts. The growth of SiNTs by molecular beam expitaxy on porous alumina, without using catalysts was also reported. The observed tubular structures were covered with a thick layer of silicon oxide. These SiNTs exhibit a photoluminescence peak at a wavelength of 600 nm. The self-organized growth of smaller-diameter SiNTs via hydrothermal synthesis, using silicon monoxide (SiO) was reported. The periodicity of the SiNTs was measured by using the scale bar of the TEM micrographs.