Many 2D covalent polymers synthesized as single layers on surfaces show inherent disorder, expressed for example in their ring-size distribution. Systems which are expected to form the thermodynamically favored hexagonal lattice usually deviate from crystallinity and include high numbers of pentagons, heptagons, and rings of other sizes. The amorphous structure of two different covalent polymers in real space using scanning tunneling microscopy is investigated. Molecular dynamics simulations are employed to extract additional information. We show that short-range correlations exist in the structure of one polymer, i. e. that polygons are not tessellating the surface randomly but that ring neighborhoods have preferential compositions. The correlation is dictated by the energy of formation of the ring neighborhoods.

Yttria-stabilized zirconia (YSZ) thin films were deposited using direct current (reactive and metallic) and radio frequency magnetron sputtering. The effect of the deposition technique and annealing treatment on the microstructure and crystallinity of the thin films was assessed. Using the films produced in this work, oxygen gas sensors were built and their performance under vacuum conditions was evaluated. All the films exhibited a cubic crystalline structure after a post-deposition thermal treatment, regardless of the sputtering technique. When the annealing treatment surpassed 1000 °C, impurities were detected on the thin film surface. The oxygen gas sensors employing the reactive and oxide-sputtered YSZ thin films displayed a proportional increase in the sensor current as the oxygen partial pressure was increased in the evaluated pressure range (5 × 10−6 to 2 × 10−3 mbar). The sensors which employed the metallic-deposited YSZ films suffered from electronic conductivity at low partial pressures.