IMR/SSEP Special Joint Seminar – Friday, Sept. 14

ORISadmin Events, IMR Colloquia

The OSU Institute for Materials Research is co-hosting a Solid State Electronics and Photonics (SSEP) seminar this week.

 SPECIAL JOINT SSEP/IMR SEMINAR

Lateral high-quality growth of Si and Ge on amorphous and lattice-mismatched substrates using metal-catalyzed growth

Nate Quitoriano   

Assistant Professor, Department of Mining and Materials Engineering, McGill University

FRIDAY, SEPT. 14, 10:00AM – 11:00 AM

260 Dreese Laboratory

Refreshments will be served

Abstract

A high-quality, high-throughput, direct-growth approach to the integration of semiconductors on lattice-mismatched and amorphous substrates would revolutionize large-area and cost-sensitive technologies such as solar cells.  Here, we report the growth of high-quality Si and Ge on amorphous and lattice-mismatched materials using metal-catalyzed growth at the nano-scale.  This high-quality material is grown laterally over the substrate, either amorphous or crystalline, from a single seed ensuring that the material is single crystalline and has low dislocation densities determined by diffraction-contrast transmission electron microscopy.  The lateral growth of films and engineering of one nucleation site is enabled by the use of guided, selective, metal-catalyzed growth.  In this growth process, which is reminiscent of the Bridgman crystal growth process, it is likely important that the catalyst is a liquid at the growth temperature.  When growing Ge on Si, instead of nucleating dislocations from the surface, which is done in thin film growth, dislocations can form as the growth front moves laterally and accommodate the lattice mismatch.  In this manner, dislocations reside solely at the interface between the film and substrate extending from one end of the film to the other. We discuss our results at the nanoscale and describe a method to scale up this technology towards the wafer-scale and beyond.  Various applications are discussed including sensors and photovoltaics. Successful growth of high-quality, single-crystalline, semiconductor films on cheap, possibly amorphous, substrates would lead to the most efficient solar cells on cheap and large substrates and enable economies of scale.

Biography

In 2000, Nate Quitoriano received B.S. degrees in both Electrical Engineering and Computer Science and Materials Science and Engineering from the University of California, Berkeley.  As an undergraduate, he worked with Tim Sands on an establishing the kinetics of an ohmic, transient-liquid-phase bond for semiconductors. Nate received his Ph.D. in Materials Science Engineering in 2006 at MIT under the supervision of Gene Fitzgerald.  While at MIT, he worked on III-V, lattice-mismatched semiconductors and grew high-quality InP on GaAs using graded, compositional buffers to slowly increase the lattice constant. Following MIT, he worked in Stan William’s group at Hewlett-Packard Labs under Ted Kamins where he studied Si and Ge nanowires for use as sensors and electrical devices and successfully demonstrated Si nanotube resonators and guided Si nanowire growth.  Nate is now Assistant Professor of Materials Engineering at McGill University where his lab researches the growth of metal-catalyzed and liquid-phase epitaxial semiconductor growth as well as optical waveguide modeling.