Excimer laser crystallized silicon films have been studied as a function ofthe number of laser shots, and the influence of the use of suchpolycrystalline films in thin film transistors (TFTs) has also beeninvestigated. It is found that electron Mobility, one of the most importantof all TFT characteristics, increases monotonically with the number ofirradiations, with maximum mobility being obtained at about 20 shots. Thisresult is not due to grain size, since transmission electron microscopyindicates that the number of laser shots does not affect grain size inpolycrystalline silicon films. Raman studies and TFT carrier transportanalysis, on the other hand, suggest that this increase in electron mobilitymay be explained by the decrease in grain boundary defects and defectsinside grains.

Whiskers of 2212 phase Bi2Sr2Ca1Cu2Ox were prepared by heating in air the powder-compacted pellets of melt-quenched glassy products in BiSrCaCu2Ox containing a small amount of Al2O3. The dissolved and/or physically mixed Al2O3 in the powder-compacted specimen is found to enhance the whisker formation remarkably.

The melts of BiSrCaCu2Al0.5Ox were quenched by vacuum casting into fine fused silica tubes (≍ 2 mmÏΦ), resulting in the formation of glass rods. The oxygen absorption during the reheating of the glass specimens was studied by thermogravimetric analysis. It was found that the superconducting properties of glass-ceramics depend on the amount of the oxygen absorption of the specimen during heating and cooling. The increase of Tc with the annealing at lower temperatures was explained in terms of increasing of oxygen in the specimen.

Superconducting properties are studied for glass-ceramics which were prepared by reheating glass rods and the glass powder compacts in the BiSrCaCu2Al0.5Ox system, respectively. The glass-ceramic rod specimens obtained by reheating rod glass at 800–830 °C for 50 h have a Tc (R = 0) of 85 K, while the disk specimens obtained by reheating the powdered glass compacts in the same way do not exhibit superconductivity above 77 K. This difference in superconductivity between the specimens is discussed in terms of the crystallization process and the amount of oxygen absorption of the specimens during heating.