Narrow Results

The thermal decomposition pathway and desorption of diethylamido of tetrakis(diethylamido)zirconium [TDEAZr, Zr(N(C₂H₅)₂)₄] on Si(100) were studied using temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). During TPD experiments, ethylethyleneimine (C₂H₅N=CHCH₃), diethylamine [NH(C₂H₅)₂], acetonitrile (CH₃CN), ethylene (C₂H₄) and hydrogen (H₂) desorbed as the main decomposition products of diethylamido, which was chemisorbed on Si(100) through the scission of the zirconium–diethylamido bond in TDEAZr. After TPD runs, the formation of silicon carbide and silicon nitride was observed on the surface by XPS, indicating that a complete decomposition of diethylamido proceeded. This could be a reaction pathway of C, N incorporation in the thin film growth using TDEAZr as a Zr precursor.

The decomposition of goethite and goethite/siderite concentrates into hematite with thermal modification was studied through the measurements of X-ray diffraction (XRD), scanning electronic microscope (SEM) and thermal gravimetric analysis (TGA). The experimental results showed that goethite decomposed into hematite directly at around 300°C without any intermediate phase and the decomposition of siderite completed at 500°C. Nanoscale granular structures were observed in the thermally treated products. It deserves highlighting that the decomposition processes proceeded from surfaces into bulks.