preparation can be applied to almost any material type-hard, soft, or combinations thereof. The number of materials for which successful TEM sample preparation with FIBs has been documented certainly reaches several hundred and spans from hard matter such as metals, ceramics, and composites to soft matter including polymers, biological materials, and even frozen liquids.The main disadvantage of FIBs, however, is caused by the nature of the milling process: the ion collisions initiating sputter removal can also lead to ion implantation and cause severe damage to the remaining bulk of the material. As the FIB lamellae method spreads to more advanced TEM techniques, various procedures have been developed to reduce or repair this damage.In this article, the major specimen preparation techniques are reviewed; the consequences of FIB-induced damage are discussed, along with strategies to reduce the damage; and an overview on applications in materials science and in related instrumental fields is presented. Specimen Preparation TechniquesSince the first-generation FIBs were mainly used as semiconductor tools, early attempts to prepare TEM specimens in an FIB also focused on semiconductor materials. The initial methods were based on mechanically polishing the sample down to an approximately 50-mm lamella and then using the FIB to cut two trenches, one from each side, leaving behind a thin electron-transparent lamella supported by bulk material on two opposite sides ( Figure 1). 2 Referring to the geometry seen in Figure 1, this method is frequently called the H-bar technique. This method was subsequently refined by employing a tripod polisher for the initial thinning of the thin slab, 3 which is particularly valuable in the case of complex semiconductor devices.In parallel, techniques were developed that make it possible to directly remove an electron-transparent lamella from a bulk specimen without mechanical polishing (see Figure 2). These so-called liftout techniques were first proposed by Overwijk et al. 4 and further developed to a routinely and reliably applicable technique for a broad materials range by Giannuzzi et al. 5 Whereas the first attempts were based on an ex situ lift-out of the lamella using a micromanipulator under an optical microscope, techniques based on an in situ lift-out of the lamella are gaining increasing importance. 6 Specimens extracted by in situ lift-out can be shaped in a number of different and 400 MRS BULLETIN • VOLUME 32 • MAY 2007 • www/mrs.org/bulletin AbstractOne of the most important applications of a focused ion beam (FIB) workstation is preparing samples for transmission electron microscope (TEM) investigation. Samples must be uniformly thin to enable the analyzing beam of electrons to penetrate. The FIB enables not only the preparation of large, uniformly thick, sitespecific samples, but also the fabrication of lamellae used for TEM samples from composite samples consisting of inorganic and organic materials with very different properties. This article gives an overview of the...

To meet growing demands for electric automotive and regenerative energy storage applications, researchers all over the world have sought to increase the energy density of electrochemical capacitors. Hybridizing battery-capacitor electrodes can overcome the energy density limitation of the conventional electrochemical capacitors because they employ both the system of a battery-like (redox) and a capacitor-like (double-layer) electrode, producing a larger working voltage and capacitance. However, to balance such asymmetric systems, the rates for the redox portion must be substantially increased to the levels of double-layer process, which presents a significant challenge. An in situ material processing technology called "ultracentrifuging (UC) treatment" has been used to prepare a novel ultrafast Li4Ti5O12 (LTO) nanocrystal electrode for capacitive energy storage. This Account describes an extremely high-performance supercapacitor that utilizes highly optimized "nano-nano-LTO/carbon composites" prepared via the UC treatment. The UC-treated LTO nanocrystals are grown as either nanosheets or nanoparticles, and both have hyperlinks to two types of nanocarbons: carbon nanofibers and supergrowth (single-walled) carbon nanotubes. The spinel structured LTO has been prepared with two types of hyperdispersed carbons. The UC treatment at 75 000G stoichiometrically accelerates the in situ sol-gel reaction (hydrolysis followed by polycondensation) and further forms, anchors, and grafts the nanoscale LTO precursors onto the carbon matrices. The mechanochemical sol-gel reaction is followed by a short heat-treatment process in vacuo. This immediate treatment with heat is very important for achieving optimal crystallization, inhibiting oxidative decomposition of carbon matrices, and suppressing agglomeration. Such nanocrystal composites can store and deliver energy at the highest rate attained to this date. The charge-discharge profiles indicate a very high sustained capacity of 80 mAh g(-1) at an extremely high rate of 1200 C. Using this ultrafast material, we assembled a hybrid device called a "nanohybrid capacitor" that consists of a Faradaic Li-intercalating LTO electrode and a non-Faradaic AC electrode employing an anion (typically BF4(-)) adsorption-desorption process. The "nanohybrid capacitor" cell has demonstrated remarkable energy, power, and cycleability performance as an electrochemical capacitor electrode. It also exhibits the same ion adsorption-desorption process rates as those of standard activated carbon electrodes in electrochemical capacitors. The new-generation "nanohybrid capacitor" technology produced more than triple the energy density of a conventional electrochemical capacitor. Moreover, the synthetic simplicity of the high-performance nanostructures makes it possible to scale them up for large-volume material production and further applications in many other electrochemical energy storage devices.

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