Fullerenes and Polymers Produced by the Chemical Vapor Deposition Method

Abstract

Plasma-enhanced chemical vapor deposition has been used for the deposition of diamond and diamond-like thin films during the last decade with great success. Here we present experimental evidence that a chemical vapor deposition technique can also be used to synthesize other forms of carbon including fullerenes and hydrocarbon polymers. The mechanism of diamond nucleation and fullerene formation appear closely related.Since the discovery that fullerenes form in supersonic molecular beams (7), many techniques (2-9) have been used to produce fullerenes. Out of these many techniques, carbon-arc and combustion methods have been used for commercial production of fullerenes. In the carbon-arc method, yields of 5% to 8% are common, and yields as high as 40% have been reported (JO). It has been a puzzle for some time how a molecule as complex as fullerene can be formed so readily. Various formation mechanisms have been proposed (11)(12)(13)(14). In particular the isolated pentagon rule (JPR) appears to explain many of the experimental observations.Here we present observations of fullerene formation using hot-filament CVD and microwave-enhanced CVD methods. The yields of fullerene-containing soot are low, even though the yields of fullerene from the soot are quite reasonable. Our goals in this research are: (a) to determine the relationship between fullerene formation and diamond nucleation, and (b) to shed light on fullerene formation mechanisms. ExperimentalHot filament CVD A schematic diagram of the apparatus (75, 16) used for this study is shown in Fig. 1. The chamber is constructed of stainless steel with a diameter of 35

A Review of Carbon Nanomaterials’ Synthesis via the Chemical Vapor Deposition (CVD) Method

“…Fullerenes can be synthesized using several techniques; the most commonly used ones are laser ablation [ 25 ], arc vaporization of graphite [ 25 ], and CVD methods [ 34 , 35 ]. Fullerenes are traditionally produced by the CVD method, combustion processes and arc-discharge vaporization of graphite.…”

“…The CVD method for the production of fullerenes, however, has the advantage that lower temperature is required as compared to laser vaporization and arc discharge. Kleckley et al [ 34 ] presented two methods for the synthesis of fullerene that are hot-filament CVD and microwave-enhanced CVD methods.…”

“…A schematic diagram of the hot-filament CVD is shown in Figure 3 [ 34 ]. The chamber is constructed of stainless steel with a filament made of tungsten wire.…”

“…Microwave CVD apparatus is presented in Figure 4 [ 34 ]. A quartz tube was used as a reaction chamber.…”

“… Schematic diagram of the hot-filament chemical vapor deposition (CVD) chamber. Reproduced with permission from [ 34 ]. Copyright (1997) American Chemical Society.…”