Day 1 :
Keynote Forum
Ryan Mc Clintock
Northwestern University, USA
Keynote: Wide band gap III-nitride semiconductor devices
Time : 08:30-09:00
Biography:
Ryan McClintock has received his BS and PhD degrees in Electrical Engineering from Northwestern University, Evanston, IL, in 2001 and 2007, respectively. He is currently a Research Assistant Professor at the Center for Quantum Devices, Northwestern University. His primary research focuses on wide bandgap III-Nitrides for the development of ultraviolet photodetectors, lasers, and LEDs. He also has interests in the development of systems based on optoelectronic devices such as portable cameras and tunable infrared lasers. He has authored or coauthored more than 100 papers and 3 book chapters. He has received the 2007 Best EECS PhD thesis Award from Northwestern University, a Richter Trust Dissertation–Year Fellowship, a National Defense Science and Engineering (NDSEG) Fellowship, and SPIE Educational scholarship.
Abstract:
Wide Band Gap (WBG) semiconductors, such as aluminum gallium nitride (AlGaN), with its tunable direct bandgap direct bandgap covering a wide range from 0.7 eV (λ~1.8 μm) up to 6.2 eV (λ~0.2 μm), have the potential to realize efficient UV detectors and UV to visible LEDs and lasers that are currently having a transformative impact on the 21st century. However, the lack of native substrates leads to high density of crystal defects in WBG materials that limits the realization of many of these devices, especially in the more challenging high-aluminum composition regime. Overcoming these limitations has necessitated novel solutions like atomic layer epitaxy, patterned growth and even growth on highly thermal- and latticemismatched silicon substrates. By controlling the material growth, we have realized visible-blind avalanche photodetectors capable of single photon detection, some of the highest performance solar-blind photodetectors and even solar blind focal plane arrays. We have also demonstrated ultraviolet LEDs based on these WBG materials. These UV detectors and emitters find use in numerous applications in the defense, commercial and scientific arenas such as covert space-to-space communications, early missile detection, chemical and biological detection, flame detection, UV environmental monitoring and UV astronomy. By engineering the interfaces, we have been able to develop some of the first MOCVD grown intersubband devices, including everything from simple IR absorption to resonate tunneling diodes. WBG materials are unique in allowing intersubband devices in the near IR. There is also a potential to realize a room temperature terahertz quantum cascade laser.
Keynote Forum
Steven Slivken
Northwestern University, USA
Keynote: New frontiers in monolithic, tunable, mid-infrared lasers
Time : 09:00-09:30
Biography:
Steven Slivken has completed his PhD in Solid State Engineering in 2002 from Northwestern University. He is currently working as a Research Associate Professor within the Center for Quantum Devices at Northwestern Univeristy. His interests are in quantum optoelectronic devices including quantum cascade lasers. He has published more than 90 papers in reputed journals.
Abstract:
The mid-infrared spectral region (3-12 mm wavelengths) is strategic for many applications, such as chemical and biological spectroscopy, free space communcations and infrared countermeasures. Commercial systems designed to explore these applications are limited, in part, by the availability of high performance sources. For many of these applications, the definition of high performance includes the ability to rapidly cover a wide spectral region. This is especially important for chemical sensing, which can show improved specificity as the number of discretely measured wavlengths increases. While systems with multiple lasers sources can often cover a wide spectral region, this approach is extremely complicated and expensive to implement. Through advances in heterogeneous emitter gain medium deisgn, however, broadband tunable lasers can now be implemented on a single chip. Inherently compact laser architectures have been developed which do not require external feedback for tuning. The motivation for this effort is to eliminate as many external optical components as possible, which significantly reduces system size, weight and power (SWaP). In addition, production on a wafer scale can also reduce costs associated with component production and assembly. In this talk, some of the exciting new avenues of mid-infrared lasers will be described. This includes a description of how an arbitrary gain profile can be acheived, mechanisms for broadband electrical tuning and how to boost power to over a watt with on-chip amplification.