1. Glow-Discharge Plasma as a Synthetic Medium for Nanocrystalline Inorganic Non-Molecular Metal Oxides
Richard W. Schaeffer, Department of Chemistry and Biochemistry, Messiah College
A glow-discharge plasma has been used to synthesize polycrystalline films of binary metal oxides. Products from reactions of metallic copper and silver cathodes with an oxygen plasma have shown curiously wide ranging and unusual compositions, for example, CuO0.86 to CuO4.6. Moreover, the composition varies as a function of the distance between the cathode and substrate: CuO3.02±0.79 at 0.80 cm and CuO1.95±0.26 at 1.30 cm. Unfortunately, the reproducibility of these results has been poor in subsequent experiments (rsd’s of 10-50%) in part due to small product yields of 0.55 to 2.88 mg, which increase the relative uncertainty of stoichiometric determinations. Products were analyzed with powder x-ray diffraction, which revealed crystalline binary phases (CuO and Ag2O) and amorphous phases. Atomic force microscopy revealed a rough “carpet” morphology of product growing out from the surface of the substrate. The diameter of the individual “fibers” was about nm. Continued exploration and optimization of the experimental parameter space and improvements to the plasma reaction chamber design should lead to higher and more reproducible yields and ternary products.