Directed Seeding of Metal-Semiconductor Nanocomposites for Negative Index Metamaterials

Professor Rachel S. Goldman,
Department of Materials Science and Engineering,
University of Michigan

ABSTRACT: Negative index of refraction materials (NIMs) are promising for several applications including near-field imaging and steering of EM radiation. Although NIMs have been demonstrated using hybrid metamaterials at microwave frequencies, high losses and narrow bandwidths are presently limiting their wide application. We are developing a novel approach to fabricating low-loss high density NIM semiconductor-metal nanocomposites, which consists of alternating sequences of focused-ion beam nanopatterning of metallic droplet arrays and film growth using molecular-beam epitaxy. We will discuss the formation and ordering of Ga and In droplets and droplet motifs on a variety of semiconductor surfaces. In addition, we will discuss the extension of this approach to 3D. In particular, information from scattering measurements of 1D and 2D droplet motifs will be input into theoretical NIMs calculations to guide the fabrication of 3D arrays of appropriate motifs.

This work is supported in part by the IC Postdoctoral Fellowship Program and AFOSR-MURI.

BIO: Rachel S. Goldman is an Associate Professor of Materials Science & Engineering, Applied Physics, and Electrical Engineering & Computer Science at the University of Michigan (UM). Goldman received her BS degree in Physics from U of M in 1988, her MS degree in Applied Physics from Cornell University in 1992, and her PhD in Materials Science from the University of California, San Diego in 1995. Following her PhD, she was a postdoctoral fellow in Physics at Carnegie Mellon University from 1995 to 1996. In 1997, she joined UM as the Dow Corning Assistant Professor. Goldman’s research interests are in the atomic-scale design of electronic materials, with a focus on the mechanisms of strain relaxation, alloy formation, and diffusion; and correlations between microstructure and electronic, magnetic, and optical properties of semiconductor films, nanostructures, and heterostructures. Goldman received the 2002 AVS Peter Mark Memorial Award, the 2004 UM Ted Kennedy Family Team Award, and the 2005-2006 Augustus Anson Whitney Fellowship from the Radcliffe Institute at Harvard University. In addition, she has received an NSF CAREER Award (1998-2004), a UM Career Development Award (1999), and a Graduate Student Award (1994) and a Poster Award (2000) from the Materials Research Society. She is a member of the Board of Directors of AVS, as well as an Associate Editor of Journal of Vacuum Science and Technology A and Journal of Electronic Materials.