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Gamma-alumina (γ-Al2O3) is one of the most promising ceramic catalysts for the graphene growth due to its weak bonding with graphene guaranteeing excellent detachability of graphene grown on it and its use as a dielectric layer for graphene-based electronic devices. Oxygen leakage in graphene growth by chemical vapor deposition (CVD) process is unavoidable resulting in deteriorated graphene quality and device performance. This paper elucidates the role of oxygen on the growth of graphene on γ-Al2O3 quantitatively and systematically. Escaping from unreliable analysis of the oxygen concentration in the CVD tube during the process, this paper directly focuses on the oxygen contents in resultant graphene crystals grown at diversified positions along the tube displaying from 9.75% to 14.82%. Oxygen-dependent electrical properties of the graphene-based electrical devices including sheet resistance, contact resistance, and electrical homogeneity are measured to 0.82-6.64 kΩ sq−1, 0.50-4.43 kΩ mm, and 23.0-97.9%, respectively, with the sp2 densities ranging from 51.0% to 72.1%. [ABSTRACT FROM AUTHOR]

In the current study, dual-active layer amorphous indium-gallium-zinc-oxide (a-IGZO) TFT has been fabricated by sequential deposition of oxygen-rich layer on a top of oxygen-poor layer in the active layer through oxygen partial pressure control in order to improve reliability under negative bias illumination stress (NBIS) condition. The method is very simple as it is performed in situ without any post treatment. Reliability of a TFT that had a thickness of oxygen-poor layer and oxygen-rich active layer in the ratio of 6:4, quite improved with the threshold voltage shift Δ of a-IGZO TFT at around 3.2 V under NBIS condition of 1000 s in comparison with a TFT (8.5 V) that comprised only oxygen-poor active layer. The increased reliability is attributed to decrease interaction with ambient and the reduction in the total neutral oxygen vacancy concentration due to the oxygen rich layer at the back-channel region, which was confirmed by X-ray photoelectron spectroscopy (XPS) analysis. [ABSTRACT FROM AUTHOR]

Highlights: [•] We investigated current hysteresis mechanism in Pt/a-IGZO/TaO x /W structure that shows rectifying characteristics. [•] In order to understand the role of each layer and the origin of memory effect, we designed and performed two model experiments on the basis of preliminary experimental results and analysis. [•] Current hysteresis (memory effect) is attributed to the bias dependent resistance change in TaO x layer due to positively charged oxygen vacancy exchange between two oxides. [ABSTRACT FROM AUTHOR]

(Ba, Sr)RuO3 oxide electrodes have been studied for high dielectric (Ba, Sr)TiO3 film in DRAM capacitors. Metal organic chemical vapor deposition (MOCVD) is used for large-scale deposition and provides better step coverage properties. In this work, methoxyethoxytetramethylheptanedionate (METHD) precursor and solvent [n-butylacetate(C6H12O2)] were mixed together into a single solution source. Post deposition annealing is carried out in oxygen atmosphere using rapid thermal annealing (RTA) to investigate the effect of organic impurities such as carbon during deposition. After annealing, resistivity of the BSR film decreased drastically compared to the as-deposited film. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis were used to describe this phenomenon accurately. The decrease in carbonate with increasing annealing time was confirmed by XRD analysis. [Copyright &y& Elsevier]