Showing papers on "Graphene oxide paper published in 1980"

The structure of ultrathin oxide on silicon

Abstract: 30‐A‐thick oxide on silicon has been examined in cross section by high‐resolution electron microscopy. The oxide thickness was uniform to within 5 A, even though the oxide undulated up to 8 A in height and with about 50 A periodicity.

Structure of tunnel barrier oxide for Pb-alloy Josephson junctions

Abstract: The oxide formed on Pb-In and Pb-In-Au alloy films by processes similar to those used to fabricate oxide tunnel barriers for experimental Josephson junction devices has been investigated with transmission electron microscopy and diffraction (TEM/TED), Auger electron and x-ray photoelectron spectroscopies (AES and XPS), and ellipsometry. Thermal oxidation of Pb-In(13 at%) alloys at room temperature results in a noncrystalline oxide, whereas oxides formed at ≥60°C in low pressures of O2, result in a continuous stable epitaxial layer of cubic In2O3 ≅2.5 nm thick. The oxide formed by sputtering such a thermal oxide in an rf-excited O2, glow discharge (rf oxidation) results in a layered structure ≅6.5 nm thick, the bulk of which consists of an upper layer of epitaxial In2O3 and a lower layer of crystalline orthorhombic and tetragonal PbO. The thickness of the PbO layer depends on the availability of In at the metal-oxide interface, and thus, on the alloy composition and the temperature and rate of oxidation. For In concentrations above ≅18 at%, the bulk of the oxide was found to be entirely epitaxial In2O3. An additional ≅0.3-nm-thick surface layer of PbO is observed, which arises from material sputtered from the Pb-coated rf electrode and subsequently backscattered onto the surface of the oxide. Altering this backscattered material from lead oxide to indium oxide increases the current densities of completed junctions by more than a factor of 40. In contrast, variations in the composition of the lower portions of the oxide have little effect on the junction characteristics. Factors affecting the composition and reproducibility of the oxide are discussed.

Temperature stabilized silicon dioxide-mixed oxide, the process for its production and use

Abstract: There is prepared pyrogenically produced silicon dioxide-mixed oxide having a BET surface area of 50 to 400 m2 /g which contains as a constituent of the mixed oxide: 0.01 to 10 weight % zirconium dioxide or 0.01 to 10 weight % iron oxide (ferric oxide) or 0.01 to 9.9 weight % titanium dioxide. Because of the doping with the foreign oxide the silicon dioxide-mixed oxide is more temperature stable than the undoped silicon dioxide. The product can be used as thermal insulation either as unpressed material in free bulk form or as a compacted mixture.

Stored charge in anodic aluminium oxide films

Abstract: Charge storage on aluminium oxide films has been studied using the Kelvin probe technique. The experiments extend previous studies by considering oxide films ranging in thickness from 3 nm up to 240 nm. The band structure of the oxide film deduced from these measurements is discussed and related to the problem of arc root initiation in oxide covered cathodes.

Laser annealing under the oxide layers in silicon

Abstract: Laser pulses have been used to study the growth and removal of dislocations underneath thin oxide layers in silicon. These observations provide clear evidence of melting under the oxide layer without disturbing the oxide layer on the surface. The thickness of melted regions increased with increasing of stacking faults were observed, presumably as a result of melting of the oxide layer and the introduction of oxide clusters in silicon.