RESUMEN
The precise observation of a solid-liquid interface by means of frequency modulation atomic force microscopy (FM-AFM) was performed, demonstrating its applicability to a study on lead acid batteries using an electrochemical test cell for in-liquid FM-AFM embedded with a specialized cantilever holder. The consistency and reproducibility of each surface profile observed via amplitude modulation AFM and FM-AFM were verified properly in a strong acidic electrolyte. In terms of FM-AFM, the ability to observe remarkable changes in the force mapping is the most beneficial, especially near the negative electrode surface. The localization of lignosulfonate (LS) added into the electrolyte as an expander could be visualized since this characteristic force mapping was captured when LS was added to electrolyte.
RESUMEN
We investigated the oxidation of oxygen vacancies at the surface of anatase TiO2(001) using a supersonic seeded molecular beam (SSMB) of oxygen. The oxygen vacancies at the top surface and subsurface could be eliminated by the supply of oxygen using an SSMB. Oxygen vacancies are present on the surface of anatase TiO2(001) when it is untreated before transfer to a vacuum chamber. These vacancies, which are stable in the as-grown condition, could also be effectively eliminated by using the oxygen SSMB.
RESUMEN
The structure of the rutile TiO2(110)-(1 × 2) reconstructed surface is a phase induced by oxygen reduction. There is ongoing debate about the (1 × 2) reconstruction, because it cannot be clarified whether the (1 × 2) structure is formed over a wide area or only locally using macroscopic analysis methods such as diffraction. We used non-contact atomic force microscopy, scanning tunneling microscopy, and low-energy electron diffraction at room temperature to characterize the surface. Ti2O3 rows appeared as bright spots in both NC-AFM and STM images observed in the same area. High-resolution NC-AFM images revealed that the rutile TiO2(110)-(1 × 2) reconstructed surface is composed of two domains with different types of asymmetric rows.
RESUMEN
Image patterns of anatase TiO2(001) with non-contact atomic force microscopy (NC-AFM) are presented. A combined system of NC-AFM with pulsed laser deposition, scanning tunneling microscopy (STM), and low energy electron diffraction (LEED) enables us to prepare clean surfaces of anatase TiO2 thin films and to perform measurements on them without breaking the vacuum or the need of cleaning the surface with sputtering and annealing cycles. Results from STM and LEED show that the anatase TiO2(001) films display a (1 × 4) surface pattern of row structures. At far distances, in which the frequency shift was relatively small, NC-AFM images show three different patterns (labeled as protrusion, hole, and neutral contrast, respectively) similar to the ones that have been reported before in the studies of the rutile TiO2 surface. At closer tip-sample distances, a periodic pattern consistent with the TiO2 lattice constant was observed along the higher-positioned TiO3 rows. We have also observed that energy dissipation is induced only with platinum tips, and not with other tip apexes.
RESUMEN
We have designed and developed a combined system of pulsed laser deposition (PLD) and non-contact atomic force microscopy (NC-AFM) for observations of insulator metal oxide surfaces. With this system, the long-period iterations of sputtering and annealing used in conventional methods for preparing a metal oxide film surface are not required. The performance of the combined system is demonstrated for the preparation and high-resolution NC-AFM imaging of atomically flat thin films of anatase TiO2(001) and LaAlO3(100).
