Abstract
Diamond crystals have been synthesized by hot-filament CVD method (chemical vapor deposition) using methyl alcohol (CH_3OH) only. The crystals are grown on the substrate at a pressure of 760 torr. The deposited crystals are characterized by SEM observation and Raman spectroscopy. With the view of promoting science education, a diamond synthesis device can be composed of glass-bottles and ruber stoppers; it simply costs several hundred yen. The previous by reported CVD methods have used plasma to decompose the gases (CH_4,C_2H_5OH) containing carbon. It is known that one of a plasma in the atmosphere is the combustion flame. Diamond crystals with good crystallinity have been successfully grown on a substrate using oxyacetylene combustion flame in the atmosphere. The substrate had to place within a inner flame (reducing flame) of combustion flame. The growth rates of the diamond depend on substrate temperatures and gas ratios (O_2/C_2H_2). A reaction chamber is not required and therefore, the diamond synthesis is easily performed.
