Surface science of plasma exposed surfaces: A challenge for applied plasma science

This article introduces a deterministic approach to using low-temperature, thermally non-equilibrium plasmas to synthesize delicate low-dimensional nanostructures of a small number of atoms on plasma exposed surfaces. This approach is based on a set of plasma-related strategies to control elementary surface processes, an area traditionally covered by surface science. Major issues related to balanced delivery and consumption of building units, appropriate choice of process conditions, and account of plasma-related electric fields, electric charges and polarization effects are identified and discussed in the quantum dot nanoarray context. Examples of a suitable plasma-aided nanofabrication facility and specific effects of a plasma-based environment on self-organized growth of size- and position-uniform nanodot arrays are shown. These results suggest a very positive outlook for using low-temperature plasma-based nanotools in high-precision nanofabrication of self-assembled nanostructures and elements of nanodevices, one of the areas of continuously rising demand from academia and industry.     

Furanone-based antibacterial coatings: Surface science

With the growth in the aged population and the need to extend average individual healthspan, biomaterials have an increasingly important role in the development of new generation medical devices, drug delivery systems, and medical diagnostic technologies. This column seeks to provide an insight into the latest developments in biomedical materials and related technologies through brief synopses and expert commentaries of recent presentations, publications, and patents.     

Surface science studies of metal hexaborides

Abstract

Over 30 years of surface science research on metal hexaborides are reviewed. Of this class of compounds, lanthanum hexaboride has been the subject of the majority of the studies because of its outstanding properties as a thermionic emitter. The use of LaB₆ cathodes as an electron source stems from the unusually low work function of ～2.5 eV for the (100) surface combined with a low evaporation rate at high temperatures. Of particular interest has been the determination of the surface geometric and electronic structure responsible for the low work function and how the work function is affected by various adsorbates. The low-index faces of single crystals of LaB₆ and other hexaborides have been studied with a variety of ultrahigh vacuum surface science methods to gain a better understanding of the structure and properties of the clean surfaces as well as their interactions with gases such as O₂, H₂O and CO.     

Surface science studies of Cu containing back contacts for CdTe solar cells

The electronic interface properties of Cu_2 − xTe with CdTe have been investigated using in-situ photoelectron spectroscopy (XPS, UPS) in comparison to CdTe/Cu and CdTe/Te interfaces. A band bending towards the Fermi level as a result of the p-doping can be seen in the CdTe by depositing Cu_2 − xTe. Different Cu_2 − xTe films were prepared by varying the deposition parameters such as substrate temperature and deposition rate of the Cu and Te sources. For all Cu_2 − xTe/CdTe interfaces a valence band offset of 0.8 ± 0.05 eV has been found.     

Surface science and model catalysis with ionic liquid-modified materials

Materials making use of thin ionic liquid (IL) films as support-modifying functional layer open up a variety of new possibilities in heterogeneous catalysis, which range from the tailoring of gas-surface interactions to the immobilization of molecularly defined reactive sites. The present report reviews recent progress towards an understanding of "supported ionic liquid phase (SILP)" and "solid catalysts with ionic liquid layer (SCILL)" materials at the microscopic level, using a surface science and model catalysis type of approach. Thin film IL systems can be prepared not only ex-situ, but also in-situ under ultrahigh vacuum (UHV) conditions using atomically well-defined surfaces as substrates, for example by physical vapor deposition (PVD). Due to their low vapor pressure, these systems can be studied in UHV using the full spectrum of surface science techniques. We discuss general strategies and considerations of this approach and exemplify the information available from complementary methods, specifically photoelectron spectroscopy and surface vibrational spectroscopy.     

A New Technique for the Identification of Surface Background: The Surface Sensitive Bolometers

The main problem for experiments using the bolometric technique to search for rare events is the contribution of surface contamination to the background. In this paper a new technique for the identification of the origin of events will be described. The idea is to shield the main bolometer with bolometric shields. Tests on small and large prototypes and the promising results will be reported.