Electrical properties of strained off-stoichiometric Cu-Cr-O delafossite thin films.

Off-stoichiometric Cu-Cr-O delafossite thin films with different thicknesses were grown by metal organic chemical vapor deposition on substrates with different coefficients of thermal expansion. Seebeck thermoelectric coefficient and resistivity measurements were performed on the range of 300-850 K. A qualitative change in the temperature-dependence of the resistivity is observed at the temperature corresponding to the deposition process, where the transition from tensile to compressive strain takes place.

Study of Gallium-Doped Zinc Oxide Thin Films Processed by Atomic Layer Deposition and RF Magnetron Sputtering for Transparent Antenna Applications.

Gallium-doped zinc oxide (GZO) films were fabricated using RF magnetron sputtering and atomic layer deposition (ALD). The latter ones demonstrate higher electrical conductivities (up to 2700 S cm) and enhanced charge mobilities (18 cm V s). The morphological analysis reveals differences mostly due to the very different nature of the deposition processes.

Low-Temperature Growth of AlN Films on Magnetostrictive Foils for High-Magnetoelectric-Response Thin-Film Composites.

This study reports a strong ME effect in thin-film composites consisting of nickel, iron, or cobalt foils and 550 nm thick AlN films grown by PE-ALD at a (low) temperature of 250 °C and ensuring isotropic and highly conformal coating profiles. The AlN film quality and the interface between the film and the foils are meticulously investigated by means of high-resolution transmission electron microscopy and the adhesion test. An interface (transition) layer of partially amorphous AlO/AlON with thicknesses of 10 and 20 nm, corresponding to the films grown on Ni, Fe, and Co foils, is revealed.

Evidence of Negative Capacitance and Capacitance Modulation by Light and Mechanical Stimuli in Pt/ZnO/Pt Schottky Junctions.

We report on the evidence of negative capacitance values in a system consisting of metal-semiconductor-metal (MSM) structures, with Schottky junctions made of zinc oxide thin films deposited by Atomic Layer Deposition (ALD) on top of platinum interdigitated electrodes (IDE). The MSM structures were studied over a wide frequency range, between 20 Hz and 1 MHz. Light and mechanical strain applied to the device modulate positive or negative capacitance and conductance characteristics by tuning the flow of electrons involved in the conduction mechanisms.

Nanomechanical properties of distinct fibrillar polymorphs of the protein α-synuclein.

Alpha-synuclein (α-Syn) is a small presynaptic protein of 140 amino acids. Its pathologic intracellular aggregation within the central nervous system yields protein fibrillar inclusions named Lewy bodies that are the hallmarks of Parkinson's disease (PD). In solution, pure α-Syn adopts an intrinsically disordered structure and assembles into fibrils that exhibit considerable morphological heterogeneity depending on their assembly conditions.

Piezoelectric tuning fork probe for atomic force microscopy imaging and specific recognition force spectroscopy of an enzyme and its ligand.

Piezoelectric quartz tuning fork has drawn the attention of many researchers for the development of new atomic force microscopy (AFM) self-sensing probes. However, only few works have been done for soft biological materials imaging in air or aqueous conditions. The aim of this work was to demonstrate the efficiency of the AFM tuning fork probe to perform high-resolution imaging of proteins and to study the specific interaction between a ligand and its receptor in aqueous media.

Gentle and fast atomic force microscopy with a piezoelectric scanning probe for nanorobotics applications.

A novel dual tip nanomanipulation atomic force microscope (AFM) platform operating in ambient conditions is presented. The system is equipped with a high frequency quartz piezoelectric self-sensing scanning probe for fast imaging and a passive cantilever for manipulation. The system is validated by imaging and selective pushing/pulling of gold colloid beads (diameters from 80 to 180 nm).

Rapid and serial quantification of adhesion forces of yeast and Mammalian cells.

Cell adhesion to surfaces represents the basis for niche colonization and survival. Here we establish serial quantification of adhesion forces of different cell types using a single probe. The pace of single-cell force-spectroscopy was accelerated to up to 200 yeast and 20 mammalian cells per probe when replacing the conventional cell trapping cantilever chemistry of atomic force microscopy by underpressure immobilization with fluidic force microscopy (FluidFM).

Parallel AFM imaging and force spectroscopy using two-dimensional probe arrays for applications in cell biology.

Atomic force microscopy (AFM) investigations of living cells provide new information in both biology and medicine. However, slow cell dynamics and the need for statistically significant sample sizes mean that data collection can be an extremely lengthy process. We address this problem by parallelizing AFM experiments using a two-dimensional cantilever array, instead of a single cantilever.

A tuning fork based wide range mechanical characterization tool with nanorobotic manipulators inside a scanning electron microscope.

This study proposes a tuning fork probe based nanomanipulation robotic system for mechanical characterization of ultraflexible nanostructures under scanning electron microscope. The force gradient is measured via the frequency modulation of a quartz tuning fork and two nanomanipulators are used for manipulation of the nanostructures. Two techniques are proposed for attaching the nanostructure to the tip of the tuning fork probe.

Microscopic study of a ligand induced electroless plating process onto polymers.

The ligand induced electroless plating (LIEP) process was recently developed and thoroughly demonstrated with one of the most used polymers for plating processes: acrylonitrile-butadiene-styrene (ABS). This generic process is based, thanks to the use of diazonium salts as precursors, on the covalent grafting of a thin layer of poly(acrylic acid) (PAA) acting as ligand for metallic salts onto pristine polymer surfaces. This strategy takes advantage of the PAA ion exchange properties.

FluidFM: combining atomic force microscopy and nanofluidics in a universal liquid delivery system for single cell applications and beyond.

We describe the fluidFM, an atomic force microscope (AFM) based on hollow cantilevers for local liquid dispensing and stimulation of single living cells under physiological conditions. A nanofluidic channel in the cantilever allows soluble molecules to be dispensed through a submicrometer aperture in the AFM tip. The sensitive AFM force feedback allows controlled approach of the tip to a sample for extremely local modification of surfaces in liquid environments.

Poly(N-isopropylacrylamide) thin films densely grafted onto gold surface: preparation, characterization, and dynamic AFM study of temperature-induced chain conformational changes.

Thermally responsive poly(N-isopropylacrylamide) (PNIPAM) films are attracting considerable attention since they offer the possibility to achieve reversible control over surface wettability and biocompatibility. In this paper, we first report a new and simple method for the grafting under melt of amine-terminated PNIPAM chains onto gold surfaces modified with a self-assembled monolayer (SAM) of reactive thiols. The formation of homogeneous tethered PNIPAM films, whose thickness can be tuned by adjusting polymer molecular weight or SAM reactivity, is evidenced by using the combination of ellipsometry, X-ray photon spectroscopy, infrared spectroscopy (PM-IRRAS), and atomic force microscopy.