Amorphous SiOx Nanowires And Aligned Nano-Cakes: The Growth Mechanism And Photoluminescence

The growth of SiOx nanostructures nanowires and nano-cakes on Au-coated n-type-Silicon (100) substrate via thermal evaporation were studied. The diameters of the obtained nanowires varied from 20 nm to about 260 nm and 100 nm to several microns in length. Based on SVLS growth mechanism, the yield obtained decreased as the argon flow rate increased. A broad emission band from 290 to 600 nm is observed in the photoluminescence (PL) spectrum of these nanowires. There are five PL peaks: two blue emission peaks 465 nm (2.67 eV) and 482 nm (2.57 eV) and two green bands centred at 502 nm (2.47 eV) and 506 nm (2.45 eV) and one ultraviolet emission peak at 350 nm (3.54 eV), which may be related to the various oxygen defects and twofold coordinated silicon lone pair centres. Detailed characterizations on the resulting nanostructures were carried out using field-emission scanning electron microscopy (FESEM) and energy-dispersed X-ray spectroscopy (EDX) and X-ray diffraction (XRD).