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Making it work in the classroom and the lab

Assistant Professor Gregory Triplett

A series of recent events have validated Assistant Professor Gregory Triplett’s sense that he has followed the right track in pursuit of his profession of choice.

In the spring of 2010, Triplett, an electrical and computer engineer at the University of Missouri, received a coveted William T. Kemper Fellowship for Teaching Excellence, and during the recently completed academic year, 17 electrical and computer engineering students prospered academically as participants in Triplett’s NSF-funded student scholarship and retention program, InCReaCE.

Last August the faculty researcher learned that the Air Force Office of Scientific Research (AFOSR) funded one of his projects to the tune of $500,000 and this spring, Triplett’s first doctoral student, Denzel Roberts, graduated.

Life as a faculty researcher in the College of Engineering is good.

“It was my parents who pointed me in the direction of the Big Trak,” Triplett said of a childhood toy that influenced his career choice. The vehicle could drive forward, backward, stop, spin left and spin right. It beeped, buzzed, had a “photon canon” (an incandescent bulb with blue plastic filter), a 24-key membrane keypad, an encoder and magnetic clutch. It could be programmed with up to 16 steps.

Triplett also credits a high school teacher/mentor with encouraging him to use his talents in math and physics as he planned for his future.

After earning a doctorate in electrical engineering from the Georgia Institute of Technology in 2004, Triplett landed a faculty position at MU.

He believes some of his early professional success can be traced to his participation in MU’s New Faculty and Teaching Scholars (NFTS) program. That program, he said, presented him with additional tools to help him become a well-rounded participant in the world of academics.

“They sponsored various workshops and a seminar on new technologies. Any information shared was good. If I didn’t use it then, I used it later on,” Triplett said, adding that as a participant, he had to write teaching and research statements, a very helpful early exercise.

He discovered he not only enjoyed the research aspects of working in academia, but also gained a great deal of personal satisfaction from teaching and serving as a mentor.

Triplett discusses research results with doctoral students David Mueller and Denzil Roberts

Triplett became concerned about diminished student enrollment and retention rates in electrical and computer engineering — a national trend — and was compelled to apply to the National Science Foundation (NSF) for a grant to fund a scholarship and retention program.

In 2008, he was awarded $520,000 from NSF to fund a retention program he titled Increasing Retention for Electrical and Computer Engineers (IncREaCE). Eligibility is based on academic performance, personal achievement and need.

In addition to a two-year scholarship, the program provides participants with peer mentoring and tutoring services. IncREaCE scholars attend workshops on topics intended to boost their success, on such topics as course load management and emerging technologies. Additional seminars touching on professional development and leadership are offered to those in the program with an eye to their futures.

“Dr. Triplett’s main goal is to keep kids in school past their freshman year,” said IncREaCE scholar Alex Spiva. “I was open to all these new possibilities, and we had guest speakers and seminars on things like resumé building.”

A freshman from Springfield, Mo., Spiva said he was introduced to technology when, as a third-grader, he took his parent’s camcorder apart. In his first year as an electrical and computer engineering freshman, he earned a 4.0 GPA both semesters and joined a fraternity. “It’s been a lot of fun,” he said.

“What I most enjoyed about the program was Dr. Triplett’s commitment to help us. He’s a super nice guy. He was always available when we needed help,” said Spiva.

“We’re trying to be holistic, getting the students to be more engaged,” Triplett said. “Everything is a work in progress, but I would like to think there are things we are doing that will help them become accountable citizens.”

Two years later, MU rewarded Triplett’s commitment to students and teaching with a Kemper Award, a recognition that provides recipients with $10,000 to spend as they wish.

“That was a wonderful honor. It encouraged me to be even better,” Triplett said.

“Dr. Triplett is one of those instructors who sees equal value in both teaching and research and is capable of being excellent in both,” said David Mueller, one of the four graduate students being mentored in the faculty-researcher’s lab.

Mueller is working with Triplett to build lasers with a slightly different twist than those currently being constructed for the AFOSR project. The research projects use molecular beam epitaxy equipment — huge deposition systems — to fabricate lasers, photodetectors and diodes at the molecular level.

“The deposition of these devices is very complex – more than 1,000 individual layers,” Triplett said. “We have to use a high-energy electron beam to look at the surfaces while they are being constructed because they can’t be seen with the naked eye.”

The process itself can take several days to complete, depending on the complexity of the device.

Much of the optoelectronic work in Triplett’s lab — The Compound Semiconductor Device Research Laboratory — is focused within the mid-infrared spectrum. He said one of the greatest challenges in working with lasers in different spectrums — and doing so with high-optical power — is that the lasers require lots of cooling power.

“Everything we deal with in the lab involves light and energy conversion. We’re trying to get more power out and be more efficient with what we have,” Triplett said. “Each of my research students has a completely different topic. I really have to know my area,” he added laughing.

Triplett’s grant project is concerned with fabricating high power quantum cascade lasers (QCL) that will impact a number of potential applications, including a laser beam capable of secure ship-to-ship communication.

Tyler King, one of Triplett’s electrical engineering undergraduate lab assistants, has been working to fabricate vertical cavity surface emitting lasers (VCSEL) with a gain medium between two mirrors that will reflect mid-infrared nonvisible light. Such a laser might be used to pulse data, or it could be used in military counter-measure tactics, to confuse the laser tracking devices on heat-seeking missiles and divert them.

“The machines we use to make these lasers are so massive and what we make is only one millimeter by one millimeter,” King said.

Electronic modeling, simulation and analysis are completed before the lasers are built on a wafer, one molecule at a time. Various semiconductor materials and combinations of materials are used with the various projects.

King graduated in May and is excited about landing a job at Honeywell Federal Manufacturing and Technologies in Kansas City on classified projects. “They were very interested in my work with Dr. Triplett,” he said.

“Dr. Triplett is so knowledgeable and he’s a huge proponent of education,” said King. “He’ll jump at any chance to work with kids, like building flashlights at summer camp. Every student loves him.”

Michael Jendrycki, a senior electrical engineering student who will graduate in December, has been designing and fabricating thermo-photovoltaic (TPV) cells in Triplett’s lab. “I’m designing a system to characterize the cells which includes taking automated measurements of how they react to different temperatures,” he said, adding that he’s looking into what sorts of materials work best.

Jendrycki explained that eventually the cells could be placed around or over something that generates heat and they could then convert it back to usable electric energy. “It’s possible that you could have a suit made out of TPV cells and generate your own electricity,” he said.

A Naval Reserve Officers Training Corps (NROTC) student, Jendrycki believes that having a technical background and programming skills will serve him well in his immediate future career in the Navy. He said that when he gets out of the service he would like to work in an alternative energy field.

“That’s why I signed up for this research with Dr. Triplett. It’s important for this generation — and civilization in general — because we’re going to run out of oil eventually,” Jendrycki added.

“Dr. Triplett is really helpful. I’ve been in the lab well after the time he probably wanted to go home, but he stayed to help me,” said Jendrycki.

Mueller and Jeff view their handiwork, not visible to the human eye, magnified on screen.

In addition to contributing to the fabrication and processing of QCLs in Triplett’s lab, senior Reginald Jeff has been working on quantum dot infrared photodetectors (QDIP).

“These very tiny dots are used for infrared imaging,” said Jeff. “But we will need to put them in an array for that detection.”

QDIPs offer a promising optoelectronic imaging alternative in a variety of areas from military to medical applications, including tracking neurological activity.

“What really interested me about this research is that I have a brother with epilepsy and this technology may eventually be used for brain imaging,” said Jeff.

Doctoral student Mueller said the advantage of working with QCL design is that these lasers can produce a lot of beam power and that typically attainable wavelengths are in the neighborhood of nine microns. He and Triplett are interested in the three- to five-micron range and are looking at unique semiconducting materials and material combinations to get the increased power and shorter wavelength.

Mueller said he has had difficulty growing crystals on the semiconductors in depositions.

“We are looking at growing them on different surfaces of the crystals, which opens up a lot of opportunities,” Mueller said.

Triplett believes the work Mueller is doing may lead to a patent.

“If we can get the power up on these lasers, even space applications will improve,” said Triplett. “It’s a real problem that exists and if we can figure out how to do it, I’ll be a really happy guy.”

“Being a successful researcher and simultaneously getting recognition as a good teacher is a good beginning for a personal legacy,” Triplett said.

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