Properties of oxide thin films and their adsorption behavior studied by scanning tunneling microscopy and conductance spectroscopy

Abstract

The preparation of thin oxide films on metal supports is a versatile approach to explore the properties of oxide materials that are otherwise inaccessible to most surface science techniques due to their insulating nature. Although substantial progress has been made in the characterization of oxide surfaces with spatially averaging techniques, a local view is often essential to provide comprehensive understanding of such systems. The scanning tunneling microscope (STM) is a powerful tool to obtain atomic-scale information on the growth behavior of oxide films, the resulting surface morphology and defect structure.

Models in Catalysis

“…Similar procedures have been carried out for many other Au aggregates on the MgO-Ag(001) system [56]. In all cases, a negative charging has been revealed, verifying the charge-mediated binding concept for Au islands on thin oxide films [59][60][61]. Another example is electron transfer from the NiAl metal substrate through a thin alumina film into Au chains formed on its surface [62].…”

Electron trapping in misfit dislocations of MgO thin films

“…22 As FER carry most of the electron current at high bias, their availability above the MgO surface determines the image contrast in the STM. 16 Apparently, the defect lines offer no or fewer FER than the regular oxide patches and consequently appear dark ͓Fig. 1͑b͔͒.…”

“…5, 12, and 13͒ and scanning tunneling microscopy ͑STM͒. [14][15][16] However, point defects play only a minor role as electron traps due to their small abundance and low storage capacity. In fact, line defects and grain boundaries are the dominant trapping centers in real oxide supports used in catalysis.…”

Self-organized chromium oxide monolayers on Fe(001)

“…[1][2][3][4][5][6][7][8][9] In particular, the structural characterization of oxide structures is of crucial importance in order to get insight into the chemical and physical processes occuring in a variety of modern technological devices based on ultrathin oxide films, such as solid-state electronic devices, high-storage-density media, and metal oxide catalysts. In this respect scanning tunneling microscopy (STM) and theoretical modeling through density functional theory (DFT) calculations have proven to be a powerful combination to disentangle the atomic structure of well-defined oxide surfaces supported by metals.…”