Template‐Directed CVD of Dielectric Nanotubes

Abstract

Fabrication of dielectric nanotubes from silicon dioxide and silicon nitride by a template-based electron cyclotron resonance (ECR) plasma-enhanced (PE) CVD is described. The nanotubes synthesized from SiH 4 -O 2 and SiH 4 -N 2 binary source reagent systems are smooth, transparent and at least 10 lm long. A mathematical description of the template-directed nanometer-scale CVD is developed to elucidate the appropriate process parameters that enable growth of high-aspect-ratio nanotubes with uniform wall thickness. The analysis of the model, by establishing general trends between process operating conditions and geometrical characteristics of the nanotubes, clarifies the mechanism of nanoscale CVD. The dielectric nanotubes obtained provide many opportunities for fabricating composite nanostructures and nanodevices.

Free-Standing Copper(II) Oxide Nanotube Arrays through an MOCVD Template Process

“…These results are in accordance with data reported in the literature, since the use of low process temperatures, a common practice in nanoscale CVD, favors the precursor decomposition on the side-walls of the membrane pores, thus avoiding complete filling of the channels …”

Template-Based CVD Synthesis of ZnS Nanotube Arrays

“…The observed emission bands from the ZnS nanotubes in our experiments should be originated from sulfur vacancies or interstitial states, as in the bulk ZnS, [8] which is consistent with the large surface-to-volume ratio in the nanotubes configuration. Our preliminary study shows that suitable CVD process conditions, [29,30] such as reaction temperature, precursor evaporating temperature, and vacuum etc., are critical to the formation of ZnS nanotubes. The higher deposition rate, which was induced by the higher reaction temperature and the higher precursor evaporating temperature, will lead to the formation of a cover layer on the PAA membrane and block the pores, which prevents the precursor molecules from entering the pores, and therefore the nanotubes can not be formed in the pores of PAA membranes via the precursor pyrolyzing.…”

Si–O–C nanotubes from pyrolyzing polycarbosilane in a mesoporous template

“…Our previous work on the attempt to generate SiC nanotubes by catalytic pyrolysis of a Si-containing polymer only yielded CNTs [33]. On the other hand, SiO x nanotubes can be generated by various methods including direct synthesis from chemical reactions [25] and the template-modulated synthesis using a sol-gel process [26] or a plasma-enhanced CVD [27]. Silicon oxycarbide has been developed as modification of silicate glasses [34].…”

“…Nanotubes of SiC x and SiO x have attracted attention [22][23][24][25][26][27]. Synthesis of hollow SiC nanotubes is still a challenge although it has been achieved by disproportionation reaction of SiO with CNT [22,24].…”