Sub-10-nanometre metallic gaps for use in molecular electronics

This thesis presents the development of a selective-etch fabrication process to create sub-10 nanometre metallic gaps and the subsequent use of the gaps to study the electronics of nanocrystals and molecules. A complete picture of the success of the process required both examination by scanning electron microscopy as well as probing the current response to an applied bias at low temperature. The empty gaps were fully characterised before self-assembling 7 nm CdSe nanocrystals onto the metal with the help of linker molecules. The I-V characteristics of the empty gaps showed a reduction of the tunnelling barrier height from the expected value (~5.1 eV, the work function of Au) when the results were fitted to the Simmons tunnelling model for a metal-insulator-metal system. Results indicate that after the barrier height is surpassed, a transition from direct to field-effect (Fowler-Nordheim) tunnelling occurs. After CdSe assembly, the collected I-V characteristics of the system at 77 K showed varied results. Many devices displayed conductance peaks at low voltages comparable to the results of the shadow evaporation process for 4.2 nm nanocrystals (also documented in this thesis). Several devices revealed switching between multiples of fundamental curves, suggesting conduction through multiples of nanocrystals

Using solid diagrams for tangible interface prototyping

In most design disciplines, early concept development involves paper-andpencil brainstorming. However, we’ve found that when designing a tangible user interface, it’s best to start with a solid diagram—a 3D “sketch ” created using simple construction materials. In the early stages of research and concept development, solid diagrams are more suitable for rapid reconfiguration and exploration than pencil sketches. They also let us analyze modes of correspondence between physical structures and abstract-information structures. Furthermore, because we can manipulate these diagrams, they help us explore usability properties and certain design trade-offs. CREATING A SOLID DIAGRAM Professional product designers create sketches to test alternative concepts, capture fleeting mental images, and discover new configurations or relationships. This “conversation with the materials ” is central to the reflective design practitioner’s experience. 1 Computer software developers occasionally sketch their ideas, though less often—perhaps when negotiating or reinterpreting rough versions of design diagrams. However, in the case of pervasive computing and augmented physical objects, the sketch processes used to create the physical forms are often quite separate from the design of the underlying software and information structures. This work might even be performed by different people who, if they sketch at all

H.5.2 User Interfaces – Input devices and strategies,

We describe three design experiments, implementing interactive systems that explore the technical context of mobile device usage as a potential design target for tangible interaction techniques. These systems are all implemented using commodity hardware, with camera input to locate tangible interaction elements, and Bluetooth to coordinate multiple devices