Minimizing feature width in atom optically fabricated chromium nanostructures

We present a study of factors that influence the feature width of nanostructures formed by atom-optical direct-write lithography. In this process, chromium atoms travel through a standing-wave laser light field and are deposited on a surface. Due to the atom-light interaction, the atoms are focused onto the surface in the standing wave nodes, producing a pattern of parallel chromium lines with widths as small as 28 nm and a spatial period of 212.78 nm. We present calculations and measurements of feature widths representing an exploration of the effects of laser power and laser-substrate separation. Strong qualitative agreement is seen between calculations and the measurements, but the observed feature widths are uniformly larger than theoretical predictions. Experiments in which the total amount of chromium deposited is varied indicate that this difference can be attributed to chromium growth behavior.