The Effect of Water Vapor and Oxygen in the Processing Environment on the Properties of Sputtered a-Si:H Films

ABSTRACTA systematic study of the effect of the trace impurity of oxygen and water vapor in the processing environment on the infra-red (IR), optical and electrical properties, and defect density of sputtered a-Si:H films is reported. The results are that small contents of water introduced into the argon plasma extract H-atoms from the growth surface, thereby reducing total hydrogen content and polyhydride formation in films deposited at low substrate temperatures, <150°C. This leads to a decrease of the defect density, and hence, to improvements in the photoconductivity (Δσ) and the associated quantum efficiency-mobility-lifetime(ημτ) product.

Prostacyclin synthesis by vascular tissue. Effect of extracellular Ca2+

Prostacyclin (PGI2) synthesis in vascular tissue is stimulated by free Ca2+. Concentrations in excess of 4 mM result in a sustained release of PGI2, but not other prostanoids, from rat aorta. This effect arises by increased synthesis of PGI2 and not through the inhibition of its metabolism. Physico-chemical examination of serum and plasma extract has indicated that much of the PGI2-stimulating activity reported for human serum derives from the presence of free Ca2+.