Speaker:
Prof. Zetian Mi
Assistant Professor & Hydro-Quebec Nano-Engineering Scholar
Department of Electrical and Computer Engineering,
McGill University, Montreal, Quebec
Title:
Nanoscale Quantum Dot Tube Lasers on Si
Date:
Wednesday, February 24, 2010
Time:
10:00 am - 11:00 am
Location:
DC 1304
Abstract:
One critical, yet missing technology for future high-speed and
multifunctional systems is a high performance micro-/nanoscale laser
on Si. Although significant progress has been made in the development
of III-V semiconductor lasers on Si, their practical applications have
been limited, to a large extent, by the generation and propagation
of dislocations at the misfit heterointerface. In this context, we
have developed a new class of nanophotonic devices, with the use of
free-standing semiconductor tubes on GaAs and Si, that can avoid all
these issues. Such unique semiconductor nanotube architecture, formed
when a coherently strained semiconductor layer is selectively released
from the host substrate, is suspended above the wafer surface. It
offers many distinct characteristics for laser operation, including
ultrahigh Q factors, directional emission, well-defined polarization,
and the ability to precisely tailor the confined optical modes using
photolithography processes. In this presentation, I will describe
the design, fabrication, and characterization of semiconductor tube
optical cavities, wherein self-organized InGaAs/GaAs quantum dots are
incorporated as the gain media. I will also report on the achievement
of the first semiconductor tube lasers in the world, which exhibit an
ultralow threshold of ~ 4 μW at room temperature and tunable emission
in the wavelength range of 1.2 - 1.3 μm. Potential applications of
semiconductor nanotubes for quantum information processing, biosensing,
and solid state lighting will also be discussed.
Biography:
Zetian Mi is an assistant professor and the Hydro-Quebec Nano-Engineering
Scholar in the Department of Electrical and Computer Engineering at
McGill University. He received the Ph.D. in Applied Physics from the
University of Michigan, Ann Arbor in 2006. He had been a research engineer
in Picometrix Inc. (Ann Arbor, MI) from 2001 to 2003 and a postdoctoral
researcher in the Department of Electrical and Computer Engineering at
the University of Michigan from 2006 to 2007. His research interests
are in the areas of epitaxial growth of semiconductor nanostructures,
nanophotonics, and nanoelectronics. He is the founder and director of the
nitride epitaxial growth facility at McGill University. He has authored
over 100 peer-reviewed technical papers and book chapters related to his
research and has contributed to a total of 18 invited talks including
2 plenary presentations at international conferences.
Invited by:
Profs.
D. Ban
and
S. Saini
