Electrochemical Strain Microscopy with Blocking Electrodes: The Role of Electromigration and Diffusion

Electrochemical strains are a ubiquitous feature of solid state ionic devices ranging from ion batteries and fuel cells to electroresistive and memristive memories. Recently, we proposed a scanning probe microscopy (SPM) based approach, referred as electrochemical strain microscopy (ESM), for probing local ionic flows and electrochemical reactions in solids based on bias-strain coupling. In ESM, the sharp SPM tip concentrates the electric field in a small (10-50 nm) region of material, inducing interfacial electrochemical processes and ionic flows. The resultant electrochemical strains are determined from dynamic surface displacement and provide information on local electrochemical functionality. Here, we analyze image formation mechanism in ESM for a special case of mixed electronic-ionic conductor with blocking tip electrode, and determine frequency dependence of response, role of diffusion and electromigration effects, and resolution and detection limits.Comment: 41 pages, 10 figures, 3 appendices, accepted to J. Appl. Phy

Carbon nanotubes as a tip calibration standard for electrostatic scanning probe microscopies

Scanning Surface Potential Microscopy (SSPM) is one of the most widely used techniques for the characterization of electrical properties at small dimensions. Applicability of SSPM and related electrostatic scanning probe microscopies for imaging of potential distributions in active micro- and nanoelectronic devices requires quantitative knowledge of tip surface contrast transfer. Here we demonstrate the utility of carbon-nanotube-based circuits to characterize geometric properties of the tip in the electrostatic scanning probe microscopies (SPM). Based on experimental observations, an analytical form for the differential tip-surface capacitance is obtained.Comment: 14 pages, 4 figure

Pyroelectric response of ferroelectric nanoparticles: size effect and electric energy harvesting

The size effect on pyroelectric response of ferroelectric nanowires and nanotubes is analyzed. The pyroelectric coefficient strongly increases with the wire radius decrease and diverges at critical radius Rcr corresponding to the size-driven transition into paraelectric phase. Size-driven enhancement of pyroelectric coupling leads to the giant pyroelectric current and voltage generation by the polarized ferroelectric nanoparticles in response to the temperature fluctuation. The maximum efficiency of the pyroelectric energy harvesting and bolometric detection is derived, and is shown to approach the Carnot limit for low temperatures.Comment: 17 pages, 4 figures, 1 Appendi