Electronic and ionic transport underpins functionality of broad range of electronic and energy devices, and is an active field of applied and fundamental research. The lecture series on Kelvin probe force microscopy and scanning probe microscopy (SPM) based current-voltage (I-V) transport measurements introduces the basic principles of SPM techniques for transport measurements based on potential and current detection, describes the multitude of dynamics variants of KPFM, KPFM-based transport measurements, and its implementation in ambient, vacuum, and liquid environments and associated artifacts. Multidimensional current- and capacitance-based transport measurements are described. The lectures are available at YouTube: https://www.youtube.com/playlist?list=PLS6ZvEWHZ3OOkRFPTrnsV3Ej09UGUjor3.

Optimized quantitative electron-probe microanalysis was applied for compositional characterization of a ferroelectric ceramic single crystal that was made from the complex perovskite-type solid-solution (1–x)Pb(Mg1/3Nb2/3)O3×xPbTiO3 (PMNT). Cation concentrations were determined with high accuracy and ultimate relative experimental uncertainty of ≤±1%, showing that the average chemical composition of the crystal corresponds to Pb(Mg1/3Nb2/3)0.67Ti0.33O3 (i.e., x=0.33), which is close to the morphotropic phase boundary composition. Over the PMNT single crystal slight compositional heterogeneity was measured for concentrations of the perovskite B-site cations Ti4+, Mg2+, and Nb5+, with variations up to ±2.3%, whereas the Pb concentration remained uniform within a variation below ±0.5%.

In this paper, the concept of load-modulated power amplifiers (PAs) is studied. Two GaN-HEMT power amplifiers (PAs), targeted for high efficiency at maximum and output back-off (OBO) power levels, are designed, implemented, and tested across 1.8–2.2 GHz. The load modulation in the first design is realized by tuning the shunt capacitors in the output matching network. A novel method is employed in the second design, where barium–stronrium–titante is used for the realization of load modulation. The large-signal measurement results across the desired band show 59–70% drain efficiency at 44–44.5 dBm output power for both designs. Using the available tunable technique, the drain efficiency of the PAs is enhanced by 4–20% at 6 dB OBO across the bandwidth.

Piezoelectric thin films have existing and promising new applications in microwave filter technologies. The final performance depends on many parameters, and very specifically on the materials properties of each involved material. In this article, materials and properties for thin-film bulk acoustic wave resonators are discussed on some selected issues: the piezoelectric coefficients and acoustic losses of AlN, the relation of the first one with microstructural parameters, the inclusion of parasitic elements, and the merits of and problems with ferroelectric materials.

This article introduces the November 2005 issue of MRS Bulletin on the life and works of Arthur Robert von Hippel, who pioneered the interdisciplinary approach to materials research. This issue of MRS Bulletin celebrates his long life, his large volume of work, and the overall impact he had on materials research as practiced today. This introductory article summarizes the start and progression of the various fields presented in this issue, and how many were inspired directly by von Hippel's work and ways, and how new fields continue to emerge based on the same foundations of interdisciplinarity. The articles in this issue cover research areas in which von Hippel was involved, namely, ferroelectrics and magnetism; fields that thrived on an interdisciplinary approach that von Hippel represented, such as semiconductors; and areas that reflect his own vision about materials research and interests later in life, including molecular design and biomaterials. Before the scientific work is presented, the issue begins with a personal sketch of von Hippel, contributed by his son Frank N. von Hippel.

Ca-doped lead zirconate titanate (52/48) thin film capacitors were prepared on electroless nickel-coated copper foils for embedded capacitor applications. The impact of Ca doping and process parameter variations was studied. Ca addition significantly reduced the temperature coefficient of capacitance. Specifically, the temperature variation was reduced to less than 10% between 300 and 580 K through calcium addition. Optimized capacitance densities and loss tangents were 400 nF/cm2 and 0.02, respectively. Crystallization temperatures of 600 °C yielded these optimized electrical properties, while higher temperatures resulted in interfacial reactions. The influence of oxygen partial pressure during crystallization was also studied. Dielectric properties were sensitive to pO2, with optimal properties occurring in a narrow pO2 window centered about 10−3 Torr. The trends with oxygen pressure were mirrored by changes in phase assemblage. Electrical transport across the dielectric layers was not strongly dependent upon doping level. This insensitivity was attributed to a thin interfacial layer present in all samples. Interface analysis using equivalent circuit analogues showed the nature of the interface to be highly resistive (insulating), rather than semiconducting or conducting.

The substrate dependence of the ferroelectric properties of sol-gel derived BaTiO3 thin films was investigated. Thin (0.35 µm) films were deposited on Si substrates of various orientations and doping. Films deposited on p+ Si (1020 cm−3 B, 2% Ge) (110) were self-poled. The poling direction is self-restoring even after being reversed by an external bias or heated above the Curie temperature. The pyroelectric coefficient was not zero above the Curie point, which indicated that the films were permanently subjected to an electric field, which originates from the contact potential between the film and the substrate. Thisconclusion was confirmed by surface photo voltage spectroscopy. The possibility of a paraelectric to ferroelectric transition driven by an electric field due to the contact potential difference must be taken into account for dynamic random access memory (DRAM) applications.