In this work, a very high, locally applied electric field was used to induce whisker nucleation on an Sn film. The field was generated by using a conductive AFM tip and applying a voltage bias between the sample and the conductive cantilever. The tip-sample separation distance was thus controllable, and any dielectric breakdown could be avoided. At locations where the AFM tip was positioned for an extended period, minuscule whiskers were observed, whose growth direction matched vertical orientation of the field.

This work presents a preliminary experimental study on the possibility to initiate growth of whiskers on the surfaces of some technologically important metals utilizing the enhanced electric field of surface plasmon polaritons (SPPs). The results provide evidence that a relatively high concentration of what appear to be whisker nuclei form in the region where SPPs were excited, whereas no such changes are observed on the untreated surface.

This paper presents experimental results supporting a theory that electric fields accelerate the growth of tin (Sn) whiskers. We have rapidly (within one week) grown long (~100 µm) and dense (~300 mm−2) whiskers on thin Sn films. Humidity and an applied electric field are found to have a strong effect when applied together, making whiskers orders of magnitude longer and denser. An evidence of explosive whisker development is presented.

We examine the potential of Bi-Ge-Se chalcogenide glass films as materials for a new type of photovoltaic devices, referred to as junctionless nanodipole PV. Glasses of a chemical composition providing a significant optical absorption were synthesized in quartz ampoules from high-purity Bi, Ge, and Se elements by a conventional melt quenching technique. This material was then used to deposit thin films with different thicknesses on various substrates by thermal evaporation under high-vacuum conditions. The original bulk glasses and the films were characterized by electron microscopy with EDS, XRD, Raman spectroscopy, differential scanning calorimetry, and spectrophotometry. Open-circuit voltage (Voc) readings under incandescent illumination were obtained from the as-deposited and annealed films. Results from this characterization work are presented and discussed. Although the efficiency of nanodipole PV material structures, based on this material remains of no practical interest, our initial results indicate a possible path for the implementation of the nanodipole PV concept.

This work presents an analytical model of crystalline phase formation in nanoglasses of phase change memory. We describe a data loss mechanism when the cell resistance changes significantly at elevated temperatures over long periods of time with no electrical bias applied. Unlike the standard approach, which relates crystalline shunt formation to aggregates of crystalline particles forming the percolation cluster, we look at the rare events of almost rectilinear path formation in very thin structures. They can occur at crystalline volume fractions considerably lower than the critical volume fraction required for percolation. We find the characteristic parameters which can describe statistics of these rare events.

We discuss possible mechanisms for Poole-Frenkel type of non-ohmic conduction in chalcogenide glasses in the range of room temperatures. Overall, we list 8 such mechanisms, only one of which (Schottky emission) can be ruled out as inconsistent with the observations. Seven others can give more or less satisfactory fits of the observed non-linear IV curves. Our analysis calls upon indicative facts that would enable one to discriminate between the various alternative models.

A summary is presented of our theoretical and experimental work over more than two years related to switching in chalcogenide glass phase change memory. As a significant addition to the well known experiments, we have studied switching under considerably lower voltages and elevated temperatures, as well as the statistics of switching events and relaxation oscillations. Our analytical theory, based on field induced crystal nucleation, predicts all of our observed features and their dependencies on material parameters.

A theory of non-crystalline recombination junctions is developed and compared to the experimental data. Junction transport is represented as hopping in both real and energy spaces, dominated by rare yet exponentially effective optimum channels having favorable configurations of localized states. Our work correlates the current-voltage characteristics of non-crystalline devices with material parameters and predicts large non-ideality factors increasing under light, and possible variations between nominally identical devices.