Klaus Schierbaum

Cerium oxide layers on Pt(111): a scanning tunneling microscopy study

Ultrathin epitaxial layers of cerium oxide were prepared by oxidation of layers of an ordered Pt–Ce surface alloy on top of a Pt(111) single crystal. They consist of low-dimensional CeO2 islands. Atomically resolved scanning tunnel microscopy (STM) images indicate a surface structure of the fluorite-type CeO2(111) 1×1 phase and the presence of surface defects.

Epitaxial TiO2 nanoparticles on Pt(111): a structural study by photoelectron diffraction and scanning tunneling microscopy

Angle-scanned X-ray photoelectron diffraction (XPD) and scanning tunneling microscopy (STM) are used to characterise the structure of TiO2 nanoparticles grown on a Pt(111) single crystal surface. The nanoparticles grow over a well-ordered oxide interfacial layer that displays a (square root 43 x square root 43) - R7.6 degrees superstructure with a unit cell (18.2 x 18.2 A), as demonstrated by STM and low-energy electron diffraction (LEED). Our XPS Ti 2p core level spectra suggest a significant contribution from reduced titanium ions within the interfacial layer. On the contrary, according to XPS binding energy data, the nanoparticles are mostly composed of Ti(IV) ions. During the initial stage of the growth, the nanoparticles are on the average 2 nm high and about some tens of nm wide, and show a flat on-top surface, while the interparticle region show the structure of the ordered interfacial layer. During later stages of the deposition, the particles become larger and they show a more irregular, globular-like shape as well as coalescence. But, even at this stage of the growth, large interparticle regions are present. Moreover, the nanoparticles produce a distinct XPD pattern which demonstrates that they grow with a preferential azimuthal orientation with respect to the substrate surface. A simple geometrical analysis of the XPD data in terms of forward scattering events suggests that the particles crystallize in the rutile TiO2 structure and expose the (100) surface. This hypothesis is supported by means of multiple scattering simulations of the XPD patterns.

Sensing molecular properties by ATR-SPP Raman spectroscopy on electrochemically structured sensor chips

The use of electrochemically structured Al surfaces as sensor arrays for combinatorial chemistry and its detection via microscopic laser techniques from very small volumes has been explored. The methodology is based on three different techniques which will be discussed separately: firstly, attenuated total reflection (ATR) is used in connection with surface-plasmon-polariton (SPP) excitation. A thin Al layer, evaporated on sapphire or quartz and covered with a naturally grown oxide layer, provides an optimum enhancement and confinement of the electrical field close to the surface. This is revealed by calculations and experimental data. Secondly, a Raman microscope is applied, enabling chemical spot analysis in the visible and UV range with a lateral resolution close to the diffraction limit. Finally, its application to investigate electrochemically structured Al films is discussed.

Computer- Control of Surface Science Experiments with Labview

LabVIEW TM 2009-based remote and process control program for an ultra-high vacuum system and a variety of surface science experiments is presented. The apparatus consists of five individual recipients for sample preparation, surface analysis, scanning tunneling microscopy and a central chamber connecting them by means of gate-valves. All processes like electron-beam heating, ion sputtering, gas exposure, thermal and electron-beam evaporation, analysis techniques, sample manipulation can run under full automatic control; transfers are supported. A variety of useful auxiliary functions are implemented to control bake-out processes, titanium sublimation pumps, pressure regulation of leak valves but also data acquiring, automatic reporting through ftp and emails, as well as external communication and control via a TCP/IP connection with a portable PC. Important features of the software include a time- control module to operate up to five channels (repetitive heating, sputtering, gas exposure, evaporation and manipulation to evaporation positions) as well as full process control. Such tools allows us to set up automatically processed experiments that include e.g. the preparation of single-crystal surfaces, their AES (Auger electron spectroscopy) and LEED (low energy electron diffraction) analysis as well as the evaporation and various treatments of thin films.

Preface to the volume

Soybean [Glycine max (L.) Merr.] is the most important legume crop, which is a great source of both protein and oil. Soybean seeds contain approximately 40% protein and 20% oil. Soybean is an important source of protein in animal and fish feed in addition to human nutrition. In recent years, soybean is also becoming a source of biodiesel. Soybean root fixes nitrogen through symbiosis with a rhizobacterium, Bradyrhizobia japonicum, improving soil health. More than 30% of the world’s soybean crop is produced in the USA and is valued at around

Ultrathin TiOx Films on Pt(111): A LEED, XPS, and STM Investigation

40 billion annually. Brazil and Argentina are other two major soybean-growing countries, followed by China and India. Soybean was originated in East Asia. It was first domesticated over 8000 years ago in China, 5000 years ago in Japan, and 3000 years ago in Korea. It was introduced to Asian countries, such as India, Indonesia, the Philippines, Vietnam, Thailand, Cambodia, Malaysia, Burma, and Nepal between 1 AD and 1600 AD. To the major soybean-growing countries, soybean was introduced only in the recent years viz to the USA in 1765, Argentina in 1882, and Brazil in early 1950s. Over the last few years, there is a growing interest in expanding soybean cultivation in Africa. The soybean has a very narrow genetic base; most cultivars can be traced to the same handful progenitor lines. In recent years, wild species are utilized through hybridization to broaden the genetic base of modern soybean cultivars. Considering economic importance and narrow genetic base of soybean, molecular genetics and genomics approaches are becoming vital to ensure steady increases in yield potential to meet the food and nutritional demands of over 9 billion people by 2050. Fortunately, with the advent of secondand now third-generation sequencing platforms, we are able to identify and use the genetic potentials of available germplasm in designing new soybean cultivars that are expected to meet the everincreasing nutritional demands of billions of people under the changing growing conditions, anticipated from climate change. The objective of this book is to bring attention of the readers including students to the recent advances in soybean genetics, breeding, and genomics along with resources essential for highly needed genetic improvement in soybean. The book comprises 13 chapters with Chaps. 1 and 2 describing the economic importance and botanical aspects of soybean, respectively; with the last chapter (Chap. 13) providing the description and navigation of the