Invited Paper TF2-WeM10
Peter Mark Memorial Award Lecture: Molecular Beam Epitaxial Growth of Novel Plasmonic Materials: Heavily-doped Semiconductors and Topological Insulators
Plasmonic devices have great potential to advance the science and technology of photonics by confining light to subwavelength volumes. Traditional plasmonic devices in the visible spectral range have been made using metals like gold, silver, and aluminum. However, in order to create plasmonic devices at infrared and terahertz frequencies, we must look to alternative materials and heterostructures. In this talk, I will discuss our recent results on the molecular beam epiatxy growth of heavily-doped semiconductors for infrared plasmonics and topological insulators for terahertz plasmonics. We find that the morphology of heavily-doped semiconductors is significantly improved with the use of a bismuth surfactant. These improved materials are then incorporated into layered heterostructures that function as infrared hyperbolic metamaterials. These hyperbolic metamaterials show large mode indices and relatively high quality factor simultaneously, laying the groundwork for new infrared plasmonic devices. In addition to our work on semiconductors, I will also discuss our efforts on the growth of topological insulators (TIs) for terhertz plasmonics. We have found that the unintentional doping density can be reduced by a factor of two in TI thin films by growing a trivially-insulating lattice-matched buffer layer between the film and the substrate. These films can then be used as terahertz plasmonic films, which are then able to confine light into spaces 200 times smaller than the free space wavelength. Finally, I will discuss our recent efforts to grow self-assembled TI nanoparticles for use as quantum dots.