We report an experimental comparison of the rotational temperature and the gas kinetic temperature of and in a positive column discharge. The discharge is operated in an oven. The oven temperature, determined with a thermocouple, provides a lower bound for the gas kinetic temperature. An upper bound on the temperature is obtained by adding to the oven temperature a calculated increase in the gas temperature due to the discharge. The contribution of the discharge to the gas temperature is calculated under the assumption of complete conversion of input power into gas heating so that the estimate provides an upper bound. The rotational temperature of is determined directly with a Boltzmann plot of the first negative system. For , the ratio of the first minimum to the secondary maximum for the band profile of the second positive system is used to obtain the rotational temperature. We compare experimental spectra with simulated spectra generated under the assumption that the rotational temperature is equal to the minimum and maximum gas kinetic temperatures. The reliability of the rotational temperature as a gas temperature diagnostic under our experimental conditions is discussed for all bands investigated.

The substrate temperature effects on the amorphous carbon film growth were investigated, by using the deposition rates and in situ and “real-time” infrared spectroscopy in multiple internal reflection geometry. The deposition rates were decreased, in contrast with the increases of substrate temperature. The growth mode was also changed with substrate temperatures: the film growth depends on the gas phase reaction at low substrate temperature; on the other hand, at high temperature the film grows with the decomposition of the CH3 species.

Under UV irradiation in the presence of an inorganic base, aqueous formaldehyde was found to give pentaerythritol and 2-hydroxymethylglycerol as the main products, accompanied by the concomitant formation of a mixture of sugars and sugar alcohols. The results indicate that this photochemical formose reaction is considerably different in product distribution from the thermal formose reaction using the Ca(OH)2 catalyst. The detailed examination of the photochemical formose reaction was carried out in the presence of Na2CO3, and a possible scheme for the formation of pentaerythritol and 2-hydroxymethylglycerol is proposed.

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Particle transport phenomena were investigated in silane plasmas in the presence of magnetic field B perpendicular to discharge electric field E. ¿From the experimental results, it was known that silicon particles were transported in the opposite direction of the E × B drift, and the particle density was decreased with increasing applied magnetic flux density. Theoretical calculations on particle drift show that negatively charged particles can be transported in the opposite direction of E × B drift and its drift velocity is increased with B for the present experimental conditions. Both of experimental and theoretical results suggest that transport by modified ambipolar E × B drift can eliminate particles from discharge space.

We report the observation of the d 3Πg→a 3Πu Swan bands of the C2 molecule both in absorption and emission in a H2/Ar/CH4 microwave discharge plasma. The input mole fraction of methane is varied from 1% to 33%. From the observed absorptions, we calculate the column density of gas phase C2. The calculated concentration of C2 is higher in discharges containing large fractions of argon than in discharges containing large fractions of hydrogen. These observations are useful in understanding the contribution of the C2 molecule to the gas phase chemistry of the microwave plasma-assisted chemical vapor deposition of diamond.

A large volume negative ion source, which has a newly devised magnetic filter called a PG filter, was designed and tested. The PG filter produces a uniform magnetic filter field over a large extraction area of 14×36 cm2 by flowing a high current through the plasma grid itself. By optimizing the filter strength, we succeeded to produce 3.4-A 75-keV negative hydrogen ion beams for 50 ms from 253 apertures of 11.3 mm diam with an average current H− density of 13 mA/cm2.