Volume 24 Issue 7 November 2010

Yuji Kohno,¹ Eiji Okunishi,¹ Takeshi Tomita,¹ Isamu Ishikawa,¹ Toshikatsu Kaneyama,¹ Yoshihiro Ohkura,¹ Yukihito Kondo¹ and Thomas Isabell ².
1. JEOL Ltd., Akishima, Tokyo, Japan. 2. JEOL USA Inc., Peabody, Boston, MA, USA.
We have developed a new type of cold field-emission electron gun (CFEG) for a 200 kV scanning transmission electron microscope, the JEM-ARM200F. This CFEG provides a newly developed vacuum system which can evacuate the area around the tip to the order of 10^-9 Pa resulting in good stability of emission. The CFEG is thus able to produce high brightness, a small energy spread and stable emission all at the same time. The low chromatic aberration from the small energy spread (0.32 eV FWHM) improves the resolution of Cs-corrected STEM. Additionally, the small probe with its high current and small energy spread enables high-speed acquisition and high spatial and energy resolution in electron energy-loss spectroscopy. In this article we describe the design of the new CFEG and demonstrate that at 200 kV the 63 pm dumbbell of GaN (211) can be resolved and that EELS analysis with a resolution of better than 0.3 eV reveals the fine structure of the titanium L_2,3 edge.

Eduardo R. Magdaluyo, Jr., ¹ Raymond V. Rivera Virtudazo ² and Emily V. Castriciones³
1. Department of Mining, Metallurgical and Materials Engineering, College of Engineering, University of the Philippines, Quezon City, Philippines. 2. Ceramic Engineering Department, Mariano Marcos State University, Batac, Ilocos Norte, Philippines. 3. Inorganic Synthesis and Computational Research Lab, Institute of Chemistry College of Science, University of the Philippines, Quezon City, Philippines
The mesostructure and surface properties of biphenyl-functionalized organosilica molecular sieves were investigated. The hybrid xerogel material was prepared using a sol-gel route involving the co-condensation of 4,4’-bis(triethoxysilyl)biphenyl and 1,2-bis (triethoxysilyl)ethane. Transmission electron microscopy images revealed lattice fringes along and perpendicular to the pore axis and hexagonal array of mesopores. The surface area ranged from 1196.99 to 1578.57 m² g^-1 and total pore volume from 1.2 to 0.75 cm³ g^-1. No significant change was observed on the pore diameter as a function of surfactant concentration ratio and aging time.