Advances of microwave plasma-enhanced chemical vapor deposition in fabrication of carbon nanotubes: a review

Eco-friendly synthesis of carbon nanotubes and their cancer theranostic applications

“…Several techniques such as conventional pyrolysis, hydrothermal carbonization pretreatment, cyclic oxidation, combustion method, and chemical vapor deposition have been reported for the synthesis of carbon materials from biomass, but are beleaguered by some noticeable disadvantages of high temperature usage, complex processes/intricacy of scale-up, low yield/efficiency, problems in process control, and likelihood of contaminations and emission of air pollutants during the synthesis procedure. [35][36][37][38] On the other hand, the safer synthesis of CNTs, and the exact growth mechanisms of these ensued nanostructures from natural precursors/catalysts have been not entirely and analytically investigated. 39,40 Microwave (MW)-assisted production approaches with mass production capabilities can be deployed for the assembly of CNTs with added benefits of lower cost, fast reaction time, simple/time-saving purification, and ecofriendliness; 41 MW plasma chemical vapor deposition technique with advantages of non/low pollutions, significant reactivity, rapid heating, and controllability has garnered attention in the fabrication of CNTs.…”

“…The effects of crucial factors such as the reacting gases (e.g., H 2 pretreatment), nitrogen-containing additive (nitrogen-comprising gas), and appropriate MW power should be analytically evaluated. 38,43 For instance, it was indicated that the higher ionization degree could be attained with elevated MW power; additional carbon atoms could be localized for thickening of CNTs. 38 With an enhancement in the MW power and the subsequent increase in substrate temperature, the agglomeration of catalyst particles can transpire, thus culminating in the formation of CNTs with lager diameters.…”

“…38,43 For instance, it was indicated that the higher ionization degree could be attained with elevated MW power; additional carbon atoms could be localized for thickening of CNTs. 38 With an enhancement in the MW power and the subsequent increase in substrate temperature, the agglomeration of catalyst particles can transpire, thus culminating in the formation of CNTs with lager diameters. Nonetheless, in some instances, longer and thinner CNTs could be obtained by increasing the MW power due to the formation of significant amount of etching species (e.g., atomic hydrogen in the plasma) in the presence of too high MW power; outer walls of CNTs were etched away, thus reducing the diameter of ensued CNTs.…”

Strategies to improve electrocatalytic performance of MoS2-based catalysts for hydrogen evolution reactions

“…It is the most widely used technology for depositing a variety of materials in the semiconductor industry, including a wide range of insulating materials, most metal materials and metal alloy materials. [121][122][123] Theoretically, the CVD process is very simple: two or more gaseous raw materials are introduced into a reaction chamber, which then react with each other to form a new material that is deposited on the wafer surface. However, experimentally, the reaction that takes place in the reaction chamber is very complex, and there are many factors that must be considered.…”

Effect of Positive Bias and Pressure on Plasma Flow Characteristics in a Chemical Vapor Deposition Chamber

“…The MPCVD process is complex and includes a variety of physical and chemical processes that vary greatly in both temporal and spatial scales. Compared with other CVD processes, MPCVD has significant advantages in synthesizing large-area diamond films [5] and has a wider range of applicable parameters, which provides the possibility for applications in various situations [6]. It can achieve low-temperature growth [7], carbon nanotube alignment growth, and structural control [8].…”