Plasma‐Assisted Approaches in Inorganic Nanostructure Fabrication

Abstract

Plasma is a unique medium for chemical reactions and materials preparations, which also finds its application in the current tide of nanostructure fabrication. Although plasma-assisted approaches have been long used in thin-film deposition and the top-down scheme of micro-/nanofabrication, fabrication of zero- and one-dimensional inorganic nanostructures through the bottom-up scheme is a relatively new focus of plasma application. In this article, recent plasma-assisted techniques in inorganic zero- and one-dimensional nanostructure fabrication are reviewed, which includes four categories of plasma-assisted approaches: plasma-enhanced chemical vapor deposition, thermal plasma sintering with liquid/solid feeding, thermal plasma evaporation and condensation, and plasma treatment of solids. The special effects and the advantages of plasmas on nanostructure fabrication are illustrated with examples, emphasizing on the understandings and ideas for controlling the growth, structure, and properties during plasma-assisted fabrications. This Review provides insight into the utilization of the special properties of plasmas in nanostructure fabrication.

Supported plasma-made 1D heterostructures: perspectives and applications

“…In that case, it is found that the plasma deposition occurs preferentially on the metal particles that act as growing centres of the oxide nanostructures. This behaviour is illustrated in Figure 3 showing a series of cross section micrographs of TiO 2 deposited at 130 ºC (i.e., amorphous TiO 2 ) and 250 ºC The facts that the deposition was carried out at relatively low temperatures as measured by a thermocouple placed at the porthole samples and that no catalytic effect is known for silver, gold or platinum towards the growth of titanium oxide, seem to discard that catalytic effects, similar to those claimed for the plasma formation of CNTs [25][26][27][28][29][30] …”

“…However, while the comprehension of the basic phenomena involved in the nanostructuring of PECVD oxide thin films in the absence of metals is relatively well understood [44][45][46][47][48][49], the effects induced by the presence of the metal are not yet clear and only phenomenological models exist to account for the development by plasma deposition of the NFs and related nanostructures [22,30,47,51]. In relation with the results reported here, we believe that a thorough description of the plasma sheath inhomogeneities induced by the presence of the metal seeds is a critical step in the comprehension of the plasma formation of core@shell metal/oxide NFs.…”

“…In the present work we aim to overview thickness of the metal layer, pretreatment with a plasma of oxygen, etc.) and the deposition temperature, always in ranges much lower than the usual processing temperatures utilize by other vapour or plasma based procedures [23][24][25][26][27][28][29][30]. We also try to give some explanations to account for the observed results where basic processes like stress relaxation, local confinement and deformation of the electric field associated to the plasma sheath, etc.…”

“…Recent advances in this emerging topic of plasma-assisted fabrication of nanostructures are stressed in excellent reviews on the subject [30]. Among the advantages of plasma processes, it has been quoted that they are relatively low cost procedures, environmentally friendly (i.e., solventless method) and scalable at wafer scale for direct deposition onto electronic and photonic devices while providing a precise control over the composition of the deposited materials.…”

“…Among the advantages of plasma processes, it has been quoted that they are relatively low cost procedures, environmentally friendly (i.e., solventless method) and scalable at wafer scale for direct deposition onto electronic and photonic devices while providing a precise control over the composition of the deposited materials. Due to these advantages, during the last years plasma technology has being systematically used for the fabrication of 1D nanofibres and other heterostructures [25,[29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47]. As already mentioned, most works in this field deal with the fabrication of heterostructures formed by CNTs and carbon nanofibers where the metal particle acts as a catalyst of the growth process.…”