Single Crystalline Trigonal Selenium Nanotubes and Nanowires Synthesized by Sonochemical Process

One-dimensional (1D) nanostructures of trigonal selenium (t-Se) were synthesized by the reduction of H2SeO3 in different solvents with a sonochemical method. The 1D structure of t-Se was formed by the anisotropic growth of selenium crystalline, and the morphology of the products highly depends on the reaction conditions including ultrasonic mode (e.g., frequency, power, and time), aging time, and solvent. Single crystalline trigonal selenium nanotubes with diameters of less than 200 nm and nanowires with diameters of 20−50 nm have been synthesized. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), energy-dispersive spectrometry (EDS), and Raman spectra were used to characterize the products. The formation process of t-Se nanotubes and nanowires were investigated. A sonication-induced directional growth mechanism was proposed for the formation of nanotubes. The further aging of tubes in solution leads to the collapse of the tubular structure and the formation of nanowires.