Growth Characteristics of Calcium Silicides Films from the Deposited Ca Films at the Different Sputtering Ar Pressure
Thin Ca films were deposited directly on Si(100) substrates at the different deposition Ar pressure using Radio Frequency (R.F.) magnetron sputtering system (MS) and subsequent annealed at 800°C for 2.5h or 1.5h in a vacuum furnace, respectively. The double-structure Ca2Si films and Ca5Si3 film are grown directly and individually on Si(100) substrates by an interdiffusion process between the deposited Ca atoms and Si bulk crystals, respectively. Experimental results indicated that the selective grown of a single phase calcium silicide in multiple silicide phases in Ca-Si system depends on sputtering condition, annealing temperature and annealing time, especially sputtering condition is the principal factor for the selective grown because it is close contacted with the morphological character, the bombardment defect, the nucleation density of a calcium silicide in a calcium silicides system by bombardment intensity and so on. Besides, 800°C is the adaptive annealing temperature for a single calcium silicide film growth. Keywords-Ca2Si; Ca5Si3; Nucleation; Semiconducting silicides; MS; Annealing
Empty electronic states of calcium silicides: An inverse-photoemission investigation in the ultraviolet photon range.
Etude des etats electroniques vides dans Ca 2 Si, CaSi et CaSi 2 par photoemission inverse. En comparant la theorie et l'experience des divergences apparaissent pour les positions de l'energie des structures observees. Ceci suggere l'importance des effets de l'etat final dans la photoemission inverse
EFFECT OF SAMPLE PREPARATION ON WATER TREE RESISTANCE OF XLPE/SEBS BLENDS
The effects of an aromatic polymer, such as poly[styrene-b-(ethylene-co-butylene)b-styrene] (SEBS), and its preparation processes on water tree resistance, morphology, crystallinity, dielectric constant and dielectric loss tangent of crosslinked polyethylene (XLPE)/SEBS and XLPE/SEBS/ethylene vinyl acetate (EVA) blends were investigated. The XLPE/SEBS samples were characterized by means of differential scanning calorimetry, scanning electron microscopy, dielectric spectral analysis and the accelerated water treeing experiment. The results clearly showed that although SEBS was partially compatible with LDPE and it was dispersed evenly in XLPE matrix, the blends demonstrated excellent dielectric performances, such as dielectric constant and dissipation factor. The crystallinity of XLPE/SEBS blends was decreased with increase in SEBS content and it was further decreased with the addition of EVA. SEBS could effectively improve the water-tree resistance of XLPE and both SEBS and EVA were found to improve the water tree resistance of XLPE synergistically as expected. The differences in sample preparation processes could change the phase morphology and dielectric performance of the blends, and could also influence the dispersion of SEBS in XLPE matrix as well as the crystallinity of the blends. Different preparation processes led to different water tree resistance behaviours of the samples. The improvement of SEBS dispersion in XLPE matrix helped to improve the water tree resistance of XLPE.