Synthesis of Planar Synthetic Opals

MRSEC Participants:Daniel Husby, Nagalingam Balakrishnan

MRSEC Advisor: Associate Professor David Norris (46 Amundson Hall)

Currently semi conductors are used in computer and communication networks. As this technology begins to reach its useful limit, photons are one possible future. This future technology will require a photonic material much the same way electronics sought the semi conductor. One possible solution is the photonic crystal, a synthetic crystal where the “atoms” are nearly one thousand times larger than in conventional crystals. Also of interest is the fact these solids are nanostructured on an optical length scale. Diffraction can cause the propagation of light to be modified within the material. Thus, photonic crystals hold great promise for revolutionizing the current electronics industry, possibly enabling optical integrated circuits.

To fabricate photonic crystals we will follow a two step procedure. The first step involves formation of synthetic opals, which will be used as the template from which silicon inverse opals (photonic crystals) will be formed. We will prepare the template from silica spheres, these spheres are formed by reacting ethanol, water, ammonium hydroxide and tetraethylorthosilicate. The amount of each chemical controls the size of spheres obtained. We will explore these chemical combinations to improve the quality of the silica spheres. Through particle analysis the size of the spheres will be determined.

The second step involves the actual formation of photonic crystals. A substrate is placed into the suspension of silica spheres. Under the proper conditions evaporation leads to deposition of an opal of uniform thickness.This material is the eventual goal of the project.

The anticipated results from our methodology quite simply are a large quantity of high quality planar opals. These planar opals can then be used to create high quality inverse opals (photonic crystals). Our fellow researchers will then have enough raw materials to further their own experiments. Thus furthering the cause of photonics in future technology.