Sabbatical Travel and Research Year for O'Shea
After being at Kansas State for 16 years I decided to take my first sabbatical. I was prompted to do this for two reasons. Firstly I was just beginning a new project on hard magnetic materials that I had received funding for and secondly I knew of some very interesting work going on in France at Grenoble on magnetic materials. The time off from my departmental duties allowed me to devote a large portion of time to pursuing these interests.

At Kansas State I worked with postdoc Hai Jiang and graduate student Radu Andresscu to make very thin(50-500 nm) permanent magnets using NdFeB and SmCo alloys. They made significant progress in this work obtaining very large coercivities and energy products for these materials and published 5 papers in various journals on this work.

In Grenoble I visited the Laboratoire Louis Neel, CNRS(Center National de la Recherche Scientifique) and learned about the work of professor Barbara and Werner's group on properties of single magnetic particles with size in 10 nm range. These measurements are actually made using a superconductor as a probe of the magnetic properties of the particle. Work has now begun at Kansas State to make some of these magnetic material/superconductor systems and study their properties.

Finally, a nice thing about a sabbatical is that time is flexible - one can choose the time at which to take vacations. Having a sabbatical allowed me to take a four week vacation in April of 2000 to Nepal. I did a beautiful but somewhat difficult hike upto 17,000 ft to the Everest basecamp and then went up to an overlook at 18,000 ft. This was once in a lifetime experience that allowed me to see a country halfway around the world with unique mountain scenery.

-Mick O'Shea


Graduate Thesis Defenses During 2000 in Physics

Jizhong Li, (PHD Defense),
"Transport Properties of III-V Nitrides Epilayers and AIGaN/GaN Heterostructures", Feb. 1, 2000.
Major Professor Hongxing Jiang. Currently at Sarnoff corp., NJ.

Weibin Fei, (PHD Defense),
"Study of Structural and Thermodynamic Properties of Bimetallic Surfaces", Feb. 14, 2000.
Major Professor Talat Rahman. Currently at Neurometrics Institute, Berkeley, CA.

Eric Wells, (PHD Defense),
"Charge Transfer in Very Slow H+ + D(1s) Half Collisions", Feb. 15, 2000.
Major Professor Itzik Ben-Itzhak. Currently a Postdoc at University if Virginia, Charlottesville, VA.

Hong Liu, (PHD Defense),
"Molecular Dynamics Studies of Polymers in Solution and at Interfaces", Feb. 21, 2000.
Major Professor Amit Chakrabarti. Currently at Sprint Corp., Kansas City, KS.

Ke-Cai Zeng, (PHD Defense),
"Optical Properties of III-Nitride Semiconductors", Apr. 12, 2000
Major Professor Jingyu Lin. Currently at Phase Metrics, Fremont, CA.

Christopher Ellis, (Master's defense),
"Optical Properties of Rare Earth Doped GaN Epilayers and AIGaN Alloys", May 10, 2000.
Major Professor Hongxing Jiang. Currently at Sprint Corp., Kansas City, KS.

Andrew K. Alton, (PHD Defense),
"Observation of Neutrino Induced Nuetral Current Charm Events", Aug. 4, 2000.
Major Professor Tim Bolton. Currently a postdoc at University of Michigan.

Ashis Mukhopadhyay, (PHD Defense),
"Ellipsometric Study of Surface Phenomena", Sept. 26, 2000.
Major Professor Bruce Law. Currently a postdoc at University of Illinois, Urbana-Champagne.

Ahlam AL-Rawi, (PHD Defense),
"Theoretical Studies of Anharmonic Effects on Metal Surfaces", Oct. 10, 2000.
Major Professor Talat Rahman. Currently a Research Assistant at KSU.

Jesse M. Goldman, (PHD Defense),
"A Next-to-leading-order QCD Analysis of Charged Current Event Rates from N Deep Inelastic Scattering at the Fermilab Tevatron", Nov. 10, 2000.
Major Professor Tim Bolton. Currently a Fellow of the Japan America Science Consortium(Tohuku University and Berkeley)

Will Hageman, (Master's Defense),
"Two Dimensional Fractal Aggregates in an acetylene Flame", Dec. 8th, 2000.
Major Professor Chris Sorensen. Currently an M.S. Student in Electrical Engineering at KSU.


Undergraduate Physics Degrees Awarded

Matthew crawley. Currently working for Anderson Consulting in Kansas City.

Chad May. Currently working as a research assistant in the Macdonald Lab and doing an M.S. in electrical engineering at KSU.

Jeff Pruitt. Currently working for ITT space systems.

Marisa Shiedeler. Currently working at the Kansas Cosmosphere in Hutchison, KS.

Brian Stevenson. Currently commissioned in the U.S. army.

Roger Thuma. Currently doing a Ph.D. in physics at KSU.

News From Semiconductor Group

The Year 2000 was another exciting year for the semiconductor group(Hongxing Jiang and Jingyu Lin). There were a lot of changes in the group. Dr. Robin Mair finished his two-year postdoctoral work here and took a job with Rudolph Technology(NJ). Zhizong Li and KeCai Zeng completed their PhDs and took jobs with Sarnoff Corporation (NJ) and Phase Metrics(CA), respectively. Chris Ellis got his MS degree and now works for Sprint in Kansas City. The research funding for the group is still going as strong as ever and the laboratory is still filled with 14 people including a few new members.

The group is currently engaged in micro- and nano-photonic research. They have pioneered the fabrication of micro- and nano-size photonic structures and devices based on Gallium Nitride (GaN) wide bandgap semiconductors by e-beam and photo-lithographic patterning and plasma etching. The group has made the transition of tiny micro-size light emitting diodes(LEDs), for the first time, from basic research to practical device components. They have succeeded in interconnecting together hundreds of blue microsize LEDs (approximately 10 microns in diameter) made from Indium-Fallium-Nitride and Gallium-Nitride (InGaN/GaN) single quantum well grown by metal organic chemical vapor deposition (MOCVD). These interconnected micro-size LEDs fir into the same device area taken up by a normal size LED of about 300 microns by 300 microns. It is believed that this novel device can overcome the two biggest problems facing LEDs: the low extraction efficiencies due to the total internal reflection occurring at the LED/air interface and the problem of current spreading. It was shown that the overall quantum efficiency was increased by as much as 60% in interconnected micro-size LEDs over the normal size LEDs. Finding methods for increasing LED efficiencies is a key step for a wide variety of applications such as full color displays and white LEDs for room lighting. The work has stimulated great interest in the optoelectronic scientific community and will be featured in several popular magazines, including Compound Semiconductor (Novermber 2000 issue and featured on the magazine's cover), Laser Focus World (December 2000 issue), and Photonic Spectra (December 2000 issue).

Most recently, the group has successfully fabricated a prototype blue microdisplay from InGaN/GaN quantum well micro-size LEDs. The device has dimension of 0.5 x 0.5 mm2 and consists of 10 x 10 pixels of 10 microns in diameter. Although this device is tiny, it can provide a virtual image comparable to viewing a 21-inch diagonal TV/computer screen when put into eye glass headset and viewed through a lens. A few years down the road, with the use of these type of microdisplays, you may be able to work with computers and wacth TVs without a real monitor. This would provide you with more mobility, privacy and fun. This year, the group's work has resulted in two patents(one pending) and more than 20 publications in professional journals.

Several major instruments have been added to their laboratory this year. An atomic force microscope(AFM) is running on a daily basis for characterizing the surface morphology of crystals. The construction of a second MOCVD system for gallium nitride epitaxial growth is completed and it looks more beautiful than a $400,000 commercial system. Jing Li in the group, Bob, Dave, and Ron in the machine shop, and Mark in the elctronice shop played a major rold in this successful task. The second MOCVD system will provide us with expanded capabilities for adjusting crystal growth parameters and special device structures. The world's first(and at present the only) deep UV (down to 195 nm) MHz femtosecond laser system is running well. The group has already obtained time-resolved photoluminescence results for the AIN/GaN quantum well system in the deep UV region. The development of deep UV femtosecond lasers is expected to have a broad impact on the optpelectronic/photonic scientific community as well as on medical research.

-Hongxing Jiang
-Jingyn Lin

 

Copyright © 2001 K-State Physics Department