Silica whispering gallery mode (WGM) microcavities were fabricated by the buffered oxide etcher and potassium hydroxide wet etching technique without any subsequent chemical or laser treatments. The silicon pedestal underneath was an octagonal pyramid, thus providing a pointed connection area with the top silica microdisk while weakly influencing the resonance modes. The sidewalls of our microdisks were wedge shaped, which was believed to be an advantage for the mode confinement. Efficient coupling from and to the 60 µm diameter microdisk structure was achieved using tapered optical fibres, exhibiting a quality factor of 1.5×10 4 near a wavelength of 1550 nm. Many resonance modes were observed, and double transverse electric modes were identified by theoretical calculations. The quality factor of the microdisks was also analysed to deduce the cavity roughness. The wet etching technique provides a more convenient avenue to fabricate WGM microdisks than conventional fabrication methods.
Fabrication of patterned one-dimensional (1D) nanostructures was recognized as the key process for the construction of functional display devices. In current investigation, we put forward the large-scale and uniform growth of patterned 3C-SiC nanowire arrays assisted by the patterned Au catalysts on SiC wafer substrate. The as-fabricated SiC nanowires presented tapered configuration with a typical bamboolike body as well as clear and sharp tips. The as-fabricated SiC nanoarray cathode has outstanding field emission (FE) characteristic that has a low turn-on field (E to ) of ~ 1.54 V/μm. The mechanism for their electron emission behaviors has been proposed.
In the present work, we reported the growth of silicon nitride (Si3N4) microrings formed by self‐coiling of nanobelts with a typical saw‐like structure on one side, which were synthesized via catalyst‐assisted pyrolysis of organic precursors. The as‐grown microrings were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X‐ray diffraction (XRD). The pyrolysis temperature played a crucial role in the self‐coiling of Si3N4 microrings, enabling the tailored growth of Si3N4 microrings. The mechanism for the growth of Si3N4 microrings was discussed, which mainly involved the growth of Si3N4 nanobelts via a vapor‐solid (VS) process, followed by bending into a ring‐like shape driven by the surface stress.
In this work, for the first time, we reported the fabrication of polymer‐derived amorphous SiCNO ceramics via electrospinning of tetraethoxysilane (TBOS), polyvinylpyrrolidone (PVP), cetrimonium bromide (CTAB), and urea combined with subsequent air calcination. The resultant products exhibited a well‐defined one‐dimensional (1D) hollow fiber nanostructure with mesoporous walls. The BET surface area of SiCNO hollow nanofibers is ~95.6 m2/g, and the average pore diameter is sized in ~9 nm. The movement of urea within the core of the as‐spun polymeric fibers accounted for the formation of hollow nanofibers, and the thermal decomposition of polymers such as PVP, TEOS, and urea responded for the formation of mesopores within the walls. In addition, it was found that the contents of urea within the raw materials played a critically important role in the formation of SiCNO mesoporous hollow nanofibers, making their growth in a controlled manner.
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