Superlattice Workshop

Development of Man Made Electronic Materials and Devices: Past and Future




May 5-7  2013  at UNC Charlotte

A Workshop recognizing 40 Years of Superlattices, Resonant Tunneling and Recent Developments
in honor of Raphael Tsu and his 25 years of Service at UNC Charlotte

The concept of man-made superlattices was introduced by Esaki and Tsu in 1970. It was recognized that such structures would show Bloch oscillations and negative differential conductance (NDC), an important property for amplifiers and oscillators.  At the time, their employer IBM did not think the topic was worthwhile. However Esaki and Tsu received a grant from ARO to pursue the topic.  These funds proved pivotal in the development of the field, allowing Tsu to develop a theoretical basis for superlattice properties.  Further encouraged by ARO, the first experiments were conducted at IBM showing a superlattice structurally but failing to show NDC. However, learning from the experience gained by Bell Labs with the DH-laser with GaAlAs as barrier to contain the excitations in GaAs lasers, negative resistance was finally observed. In those early days there was speculation that the observed effect might be a Gunn oscillation but that was soon resolved to Esaki and Tsu’s credit.  By 1996, the impact of the superlattice was enormous, leading to more than 10,000 publications and around 500 patents in the US alone.  In 1997,  The Superlattice Story’ was written under the direction of Mikael Ciftan, Chief of the Physics Division of Army Research Office.  It was sent by ARO to the White House, helped lead to the US’s  nanoscale science initiative.  Over the last 40 years, many fields have matured based on periodic quantum well structures, such as the quantum cascade laser and THz oscillators.

This workshop will celebrate these achievements and then focus on the future.  The superlattice exploits layered structures with dimensions less than the coherence length of electrons, (~10 nm at room temperature) that can exhibit quantum size effects.  For photons, coherent structures with periods of the order of the optical wavelength such as photonic crystals are being developed, as are structures with periods less than the wavelength, referred to as metamaterials.  These all exhibit remarkable properties, many of which do not occur in naturally occurring materials.  The future of engineered man-made materials continues to expand and offer new opportunities.  Hand-in-hand with this,  the future as nanoscale fabrication and other (e.g. self assembly) techniques also advance.  Man-made structures promise on-going surprises and potential for components and devices with new functionalities. This landmark workshop will reflect on the progress of the past, but very much look forward to what the next 40 years might bring. The advent of nanophotonics is rich with opportunities and challenges for managing both electrons and photons in next generation superlattice-like structures such as photonics crystals and metamaterials.

Organizing Committee

Timir Datta : Professor of Physics, University South Carolina
Nikolaus Dietz: Professor of Physics, Georgia State University
Ian Ferguson : Chairman of Electrical and Computer Engineering at UNC Charlotte
Michael Fiddy: Professor of Physics and Optical Sciences and ECE at UNC Charlotte
Richard Hammond: Physics and Materials ARO NC

Local Program Committee

Glenn Boreman: Chairman of Physics and Optical Sciences, UNC Charlotte
Wei Cai: Professor of Mathematics, UNC Charlotte
Tsing-hua Her: Associate Professor of Physics and  Optical Sciences
Na Lu: Assistant Professor of Engineering Technology
Joe Quinn: Professor of Mathematics, UNC Charlotte
Tom Schmedake: Associate Professor of Chemistry
Yong Zhang: Bissell Chair of Electrical Engineering,  UNC Charlotte

For further details contact:

Mike Fiddy                                                   
704 687 8594

Jerri Price
704 687 8404