This summer, I explored the ultra-thin film properties of P2VP. This particular polymer adheres to silicon. Typically, the adhesion only affects the layer directly attached to the silicon. However, at an extremely thin lengthscale, about 30 nm or lower, this adhesion starts to have a bulk effect on the properties of the film. I explored the effects of this nanoscale confinement on the glass transition of P2VP. The adhesion results in there being two regimes of glass transition, as marked by the linear regimes on a graph between film thickness versus temperature. This characterization allows for use of thinner and smaller technologies that are rapidly taking over technological progression.
A bump my research ran into was the analysis of extremely thin films, around 10 nm. The trend of transition showed a larger spread between the two transitions in terms of temperature to the point that at such as low temperature, around room temperature, water would condense on the film. When analyzing nanoscale thin films, water can highly skew the results. A small vacuum chamber was built in order to house the sample in order to keep water from condensing on it.
Other stages made in order to control environmental factors to expand the situations in which one can use ellipsometry include a stage meant to heat large samples uniformly. In some situations, such as a sample made on a temperature gradient, a single variable can change along a spatial dimension while keeping all others constant for high throughput analysis. A stage was constructed as proof of concept in order to keep temperature and environmental gases constant while the sample varied spatially.