Awardee Interviews | Stephen J. Pearton - 2007 John A. Thornton Memorial Award - Interview

Stephen J. Pearton

2007 John Thornton Award Winner

HOLLOWAY: Good morning. My name is Paul Holloway. I'm a member of the AVS History Committee. Today is Wednesday, September 19, 2007. We're in the University of Florida in Gainesville, Florida. I'm interviewing Stephen J. Pearton of the University of Florida, the winner of the 2007 John Thornton Memorial Award. The citation for this award reads, "For pioneering the science and application of advanced device fabrication techniques, including plasma etching, ion implantation for doping and electrical isolation, and formation of Ohmic and Schottky contacts for compound semiconductors." Steve, that's quite a mouthful. Congratulations!

PEARTON: Thank you. I appreciate it very much, and it's kind of an honor to get the Thornton Award because I didn't know John Thornton, but a few people have told me that he was a very good collaborator and a very well-liked person as well as a very good scientist. So since it's the 20th anniversary of his passing, it is kind of a nice thing for me.

HOLLOWAY: Well, I actually knew John Thornton. I interacted with him for a number of years. When I first came to the University of Florida, he actually gave us some samples of solar coupons with black metal films for absorption, and I can verify the fact that he was a superb person, a wonderful human being, and a great scientist. So I think that your comments about him are accurate. I also think it is appropriate to acknowledge that this is the 20th anniversary of his passing, which was untimely and early. But congratulations on the award. You certainly deserve it.

PEARTON: Thank you very much.

HOLLOWAY: So give us a little bit of background about yourself.

PEARTON: Well, I first became interested in science during junior high school when I had a science teacher called Mr. John Michaels, a Welshman, and he really piqued my interest in physics in particular. So when I went on to University of Tasmania, I majored in physics and just always had an interest in measuring things, understanding how things worked. The University of Tasmania was very strong in cosmic ray astronomy, optical astronomy, and infrared astronomy. We had the whole southern sky to ourselves pretty much down there. Most of the science projects that go to Antarctica leave from a home port of Hobart where the technical university is. So I finished my degree there, and I was very fortunate to get a scholarship to go and work at the Atomic Energy Commission near Sydney. That was really because my advisor in Tasmania, Peter Fenton, his former student, Alistair Tavendale, was the head of a section that became the place where I carried out virtually all my research. Alistair Tavendale was a New Zealander who had graduated from the University of Tasmania and had gone to Chalk River in Canada and had pretty much revolutionized nuclear spectroscopy by pioneering lithium doped silicon x-ray detectors. He'd gone back to Australia and he was heading a section of Department of Instrumentation Science at the AAEC. So I went up there and did all my work on my Ph.D. Through Tavendale, I made a connection with Gene Haller at the University of California-Berkeley, who was working on the same kinds of problems, and so I got a post-doc at Berkeley, which was an eye-opener for a young guy from Tasmania.

HOLLOWAY: Let me interrupt you and take you back to Tasmania for just a moment and ask what was the subject of your Ph.D. dissertation?

PEARTON: My Ph.D. was Defects and Impurities in Semiconductors for Nuclear Radiation Detectors. So it was with silicon, germanium, gallium arsenide, a little bit on cadmium telluride and mercuric iodide.

HOLLOWAY: I see. So it was electronic materials detectors.

PEARTON: Right. We grew crystals there, we fabricated the detectors, and then we did spectroscopy and measured detector resolution. We also repaired detectors for the rest of the Atomic Energy Commission, which is a spectacular process in and of itself because you have a chunk of silicon or germanium, which is about the size of a shoebox in some cases, and you have to drive lithium all the way through it. To do that, you need to keep it at constant temperature. So you have it in a liquid Freon-12 bath, and you apply a voltage to it and drive lithium for many, many centimeters into the silicon or germanium. So it was really a wonderful experience because I could work full time in kind of a professional environment. I didn't have the usual student distractions, and my advisor was a very generous person. He had already made his career pretty much and he was very supportive and arranged for me basically to go to Berkeley after I graduated.

HOLLOWAY: So when did you go to Berkeley?

PEARTON: I went to Berkeley in '82, and it was kind of an eye opener because when I first got there, I thought that half the population of the United States was either disabled or crazy because that's Berkeley. So after about a week, I realized, "I can't give a dollar to every person who asks me on the street. Otherwise, I'm not going to have any money left." Then I found out that Berkeley wasn't typical of the rest of America. There were no people living in trees in the rest of America; that was Berkeley. So I had a year there and also had a really good time. I really enjoyed working with the students there and the Professor Gene Haller. I spent most of my time at Lawrence Berkeley Lab, which is located behind the Berkeley campus.

HOLLOWAY: What were you working on there?

PEARTON: I was doing similar things. I was kind of keeping track of a lot of students, because Haller in those days was trying to set up a national lab, National Center for Advanced Materials I think it was called. So I was still working on semiconductor materials, principally germanium, silicon, and gallium arsenide, and doing defect studies and making new kinds of detectors, new types of contacts.

HOLLOWAY: This was for radiation detectors?

PEARTON: Right-radiation detectors. I also did neutron transmutation doping, where they would convert some of the arsenic or phosphorous in some of the materials to a different element and control conductivity that way. So there was a wide range of projects that I worked on, and that's been kind of typical of me. I'm not an expert at any one thing; I'm kind of broadly based, shallow, [chuckles] in most cases.

HOLLOWAY: I'm sure that most people wouldn't call you shallow! [Laughter] Productive, yes, but not shallow!

PEARTON: So after a year at Berkeley, I started interviewing. I could have stayed there for another year, but I got an offer from Bell Labs. Bell Labs in New Jersey and in Pennsylvania were desperately hiring anybody who was breathing. They had just been broken up by the Justice Department, and they were basically trying to hire as many people as they could before that took place in order to establish a high baseline for employees. So I was offered 11 different jobs I think at the different places at Bell Labs, and I took one that involved developing gallium arsenide integrated circuits because it seemed like that was the one that would give me the best chance of success.

HOLLOWAY: This was at Murray Hill, then?

PEARTON: This was at Murray Hill. I interviewed at Allentown and Reading as well. I really liked those locations, but the Murray Hill people told me that "that's not real Bell Labs out there", that was a very, very arrogant attitude, and said, "If you want to come to Bell Labs, this is the only Bell Labs location." So they took me on a tour. They showed me the lab in which the transistor was invented and the solar cell was invented, crystal growth - you know, all these methods were invented, and it was hard to turn that down. So I took a job at Bell Labs.

HOLLOWAY: You didn't need bargaining and shopping.

PEARTON: I did not need bargaining and shopping. But a person who worked in my group had known them and had many stories about them, and Bardeen was a very self-effacing, shy, diffident person. People had nothing but good things to say about him. They had nothing but negative things to say about some of his colleagues for reasons that are documented in many other places. So Bell Labs was quite an experience. I think I've told you before that one year at Bell Labs is like a dog year: it's worth seven years at some other place. Basically tremendous concentration of aggressive, ambitious people, and a lot of them are super smart, and the credit is a zero sum game. So if someone does well, that has to come at the expense of somebody else. So it was kind of a superstar system where you tried and winner take all. It was close to New York City, that same kind of mentality, and it was quite an experience. During the time I was there, I got the opportunity to work with a lot of really brilliant people, people who invented molecular beam epitaxy (MBE), like Al Cho and John Arthur, people who invented DLTS, like Dave Lang Laurie Miller, who was the co-inventor of DLTS and worked on robotics. Pierre Petroff, who was a brilliant guy with TEM and quantum dots. Kim Kimmerling, who was another brilliant guy on defect studies, Jack Rowe, who was a brilliant guy on characterization, surface studies. Many, many top people. Federico Capasso. It was quite an experience. I mean if you walk into Bell Labs, you have to bring your A game because people were aggressive. This also had some very strange people. So the first day I was there, I saw a man wearing a pith helmet with a parrot on his shoulder, and he was just walking around the corridors, and the parrot was pooping all over his shoulder and he didn't seem to pay any attention to it.

HOLLOWAY: He must have been from Berkeley.

PEARTON: Very good, Paul. Seemed like a Berkeley guy, probably. There were some very odd people. There was a man who walked backwards down the hall, and there was a medical reason for that. He had some kind of problem with his knees where his knees would give out if he went forward. So he walked backwards and nobody paid any attention to him. So okay, guy's walking backwards, there's a guy with a parrot pooping all over his shoulder - nobody really paid any attention to it. So that was a wonderful experience.

HOLLOWAY: So what are the consequences, in your opinion, of the fact that Bell Labs was broken off into 18 pieces and was destroyed by the government?

PEARTON: I think it's really a loss in the long run. Surprisingly, I think it's not until about now that we're starting to see it. I think that the time constant for its decay was long, but there were very few places in the world where there was the ability to have a lot of smart people together with almost unlimited equipment, who did research projects not having to focus on raising money, or not having to focus on teaching. If you had a question about your project, you could walk down the corridor and if you could convince somebody to work with you, then you had access to people who have invented many of these techniques. So you could make tremendous progress. I've kind of lost that feeling because of how slow things are in the university relative to other places. Two weeks was a long time at Bell Labs. You could build a lot of things. I mean, you could have a sample grown and make a device and characterize it. So when I first got to the university, I was kind of frustrated a little bit with the fact that the students had worked for years and years on things and didn't seem to have gotten that far. I think you have to recalibrate yourself and say, "Okay, it's a different goal. We're trying to educate the students." And in many cases you're not really - it's not fair to say you're not trying to solve the problem, but you are trying to explore the whole kind of parameter space and maybe set up some future work. In an industry, you're trying to solve the problem, so you're not going to spend time on things that aren't going to work.

HOLLOWAY: I remember when I first came to university, Mike White at the University of Texas-Austin, who I understand is recently deceased, gave me advice to be patient. That at a university, things move about three times slower than you expect.

PEARTON: And one of my colleagues, Mike Stavola, who's now the chair of the physics department at Lehigh told me - he left before I did - that you have to recalibrate. The conversion factor is 1 to 4. So you have four students to do the work of what you would think one person could do, because it takes them longer to ramp up, they have classes, they have internships and so on.

HOLLOWAY: They have so many distractions, so many bosses.

PEARTON: So many distractions. Even if they're focused and very good, it takes them awhile. So getting back to your question about Bell Labs, I think it's a huge loss because you just cannot - It was almost a national resource in that people would get lots of results. But one failing of the whole AT&T system was that they couldn't convert that into technology effectively. That was because you had things being invented at Murray Hill and then there was really no reward for making that into products. So you could basically throw it over the fence and hope that Allentown or Reading would pick it up. In a silly way, it was not in their interest to say that that technology worked because there was a not-invented-here syndrome, so they weren't going to get credit for it. So they would say, "Oh well, we still think there are many problems. We need to study it ourselves," and blah, blah, blah. So nothing would happen, and devices and things were not turned into products. 
Under the old system, that was fine because AT&T ran the phone network; it didn't matter if things went a little slow as long as the phone system was reliable and worked well. Just to give an example of how things changed also during my time there from hardware to software, and every three or four years they used to upgrade the speed of the phone system. So I remember the third or fourth time it happened when I was there, and they called it Project Ultra. It was supposed to get to whatever it was to 5 gigabits per second data transmission speed. So the managers at big AT&T, the parent company, had always come from telephone backgrounds, so the president of AT&T had always been someone who started up the telephone pole somewhere in Illinois, became the branch manager, head of Illinois Bell, head of the overall AT&T. So, to them, the phone system was telephone calls on wires strung between poles. It was hardware - the switches, phones - that was the thing, and they didn't have any idea about software. So we were told at one point, "Okay, we need to have the next generation of the network ready. So what do you guys need?" "Well, for us it's a shopping list. We needed 4 MBE systems and 3 of this, 5 of that," and it would typically cost about $100 million to do a project like that. So the top people at AT&T were happy to sign off on that because they understood that's how it worked. Well, the story goes, and it's probably not quite accurate but it's too good not to tell, is that there's a small software effort on the fifth floor of Murray Hill. This is where the pith helmets and the parrots were, and supposedly the story goes that two guys up there changed two lines of code in the system that ran the phone system and it made the whole system run two times faster. The top bosses said, "Hold on a second. We just have to supply these guys with donuts and coffee, and as long as they're sitting with their sandals on and doing their software in their office, we don't need $100 million to change the system if we can do it with software." At that point, there was a big change in the emphasis. So a lot of the physical lab started to disappear at Murray Hill and you saw software people coming. There was much more of an emphasis on software, and that probably had to come anyway because you can only push the hardware at a certain speed; you also need the software. 

So around the time I left, Bell Labs was changing a lot in terms of its character. We had to have customers; we had to have projects that had some goal. The old style of doing science for science's sake disappeared, and a lot of people left to go to universities. There was a lot of confusion and I'd say double dealing by the upper management. For example, just not to name anybody's name, but we had a friend who was in a tennis club with a very, very high level manager at Murray Hill, and of course when we went to these town hall meetings or whatever, they were telling us, "Oh, Bell Labs will always remain the greatest lab in the world and you guys have nothing to fear. Everything is going to be just fine." That's what he was saying in the public face, and our friend who knew him through the tennis club went and asked him, "Tell me really what's going to happen because I have an offer from a university." He said, "As your boss, you should stay here. Bell Labs is always going to be great. As your friend, you should get the hell out of Dodge because this place is going to be collapsing." So we had some contacts at University of Florida. We knew Kevin Jones, we knew Reza Abbaschian, the chair at the time, we knew Paul Holloway from conferences, and so we applied here. We needed two jobs for my wife and myself, and my wife's mother lived in Florida and so I always liked it there, kind of like Australia. So we decided. We came down here and liked what we saw. We thought about other places; there were some other options. We ended up coming here, and we've been here now for 14 years. So we're very happy people.

HOLLOWAY: We were lucky to get you.

PEARTON: Well, we were lucky I think to get the opportunity to work at the University of Florida, because the one thing you notice about Florida traveling around midwest university and even some of the California universities, they're somewhat stagnated whereas Florida is growing. Every year there's a major construction project on campus. There are major facilities. We have a strong medical school. We have a strong inter-disciplinary research community. So I think relatively speaking-professors are always complaining about their lot in life-relatively speaking, Florida is thriving.

HOLLOWAY: Right, we're doing quite well. You've done a lot of different type of activities in your career. For example, in the citation for the award, it talks about plasma etching, et cetera, but you've worked a lot with hydrogen in semiconductors. How did that come to pass?

PEARTON: That started when I was still a grad student and we saw a paper on passivating the electrical activity of defects in certain semiconductors which came out of Bell Labs, actually. So my advisor knew how to build a little plasma system, so we built one ourselves. We just made a standard vacuum system with essentially a glass bell jar, an evacuator, and you put an rf coil around it and we let it make a hydrogen plasma. Then we would take samples that we had deliberately contaminated, run the DLTS spectra on them, show that they were full of impurities, and then we would expose those samples to the hydrogen plasma and we would measure them and show that the electrical activity had disappeared. So that was kind of a simple project for us. It involved vacuum science, which was making the plasma system, and we had the characterization, we had all the samples we could deliberately contaminate them in diffuse concentrations. So it was really simple to do.

HOLLOWAY: And that was your Ph.D. work?

PEARTON: That was one chunk, I think, of my Ph.D. work, and then when I went to Berkeley, I kind of continued that.

HOLLOWAY: Gene Haller at UC-Berkeley had some experience in that area, too, I believe.

PEARTON: He actually had a very, very smart project on measuring the effects of tritium in germanium by incorporating tritium into the germanium and then making the radiation detector out of it. The tritium is kept self-counted within the detector, so you can back out how much is in there, which tells you the solubility of hydrogen in the tritium. It's a very clever approach So there were lots of things that were interesting about hydrogen. When I got to Bell Labs, people realized not only was it passivating deep impurities it was also passivating the shallow dopants. So there was a whole new field. I was fortunate to work with my friend Mike Stavola on that during my whole time there. 

HOLLOWAY: You worked a lot on other processing technologies - reactive ion etching and ion implantation. What do you consider to be significant contributions that you've made in those areas?

PEARTON: Well, my real job when I went to Bell Labs was to develop ion implantation doping of gallium arsenide. So I worked out all the annealing processes and had them implemented for the electrical activity. Then I moved on from that to dry etching because it turned out that we needed an ability to pattern pieces at a small size, and we were using wet etching and it wasn't working very well. The second RIE system ever built by a plasma firm is in a storage area on the fifth floor of Bell Labs. They had built two, one for Evelyn Hu and one for Rich Howard. They worked on them for a while and they really didn't have an application, so those things were put in storage. So we rolled one of those out and got it working again. I felt the dry etching was not too dissimilar to ion implantation. It's a different energy range, but it's the same thing of ions hitting and altering the surface. I was responsible for all the characterization done in our department, and I found dry etching to be a fairly simple thing to move on to. One of the beauties of being at Bell Labs was you did move onto things every six or seven months, and you really didn't have time to stop and think, "Well, I need to learn something about dry etching." 
So I started working on it, and for probably two years, I did a lot of etching and the processing was working out fine. Then I realized I really didn't know anything about dry etching. So I went to a short course that Joe Cecchi and some of his colleagues were running for the AVS at that time around Princeton. I think they were just about to move on from the Tokamak research. But I went there and my eyes were opened, because I realized I knew nothing about the fundamentals of dry etching even though I was doing it on a daily basis. So that was a connection through AVS. If I hadn't gone to that short course, I probably still wouldn't know anything about etching. That was around '88 or something like that. 

Then I realized that AVS was a very useful tool to me in my career, so I started attending meetings not only because I was going to short courses, but I soon realized that the technical level of AVS meeting presentations was superior to most other societies. The APS had very short, 10-12 minute presentations. MRS had been 15 or 20 minutes. They cut that back to 12, and what I started noticing was that someone could give a presentation without any data in those societies - they could get up and they give introductory things, big spiel about why they're doing it, then they would just kind of say, "Well, these are our future plans and here's the acknowledgements." It's like, "Well, I didn't really need to hear all that." So at AVS, you were forced to have something substantial because the talks were 20 minutes, and I just noticed that the technical level of presentations was better. The equipment show was the best of any of the societies, and in the AVS I've met a lot of people who are doing interdisciplinary type work. So for me, etching doing ion implantation and surface analysis, the AVS was kind of a natural home.

HOLLOWAY: Well certainly AVS has been a home for the ion etching and a lot of those process developments for semiconductors. In fact, we have a strong contribution from IBM in that area.

PEARTON: John Coburn.

HOLLOWAY: John Coburn and Harold Winters. How do you see the interaction between Murray Hill, Bell Labs, and IBM labs?

PEARTON: I noticed kind of a love-hate relationship there. We had a big plasma etching community at Murray Hill, a lot of smart people, pioneers in the field - Dale Everson, Rick Gottsho, and a number of others. They had done some of the early work. They had disagreements with Coburn and Winters in some of the literature. I think both parties made tremendous contributions. The thing that AVS kind of forced the plasma etching community to do was that there was tendency for plasma etching to be rather academic or to be too technological, when you're just trying to make a recipe and you just want to make it work and not really understanding why. So there was a famous example in the late '80s or '90s where the very first vertical cavity surface emitting laser (VCSEL) was published by Bell Corps, which was kind of a spin-out of Bell Labs. It turned out that the plasma etching for that had been done at Bell Corps, not done at Bell Labs, and the reason was that we had all of these extremely knowledgeable people on etching, but they weren't spending their time actually etching things; they were studying the systematics, which is critical for good understanding of the basic science. So the management at Bell Labs said, "We need both of these things. We need to have people who understand the plasma physics and the ion densities and the fluxes and all that stuff, and we also need to have etching systems that are etching samples." 

So AVS was a natural home for both of those communities to meet together and learn from each other. So both IBM and AT&T made their contributions. I think Winters and Coburn are absolute giants in the field. They were the first to show the synergy between the ion-assisted etching and the chemical component. In other words, that the overall etch rate is faster than the sum of the two components. That was huge. So John Coburn is still around at the meetings and he's always is extremely patient, he is very good-natured with the students, a wonderful role model. He still teaches a short course with my friend Randy Shul from Sandia. So it's always a pleasure to run into him.

HOLLOWAY: Another of the technologies you worked on is contacts to semiconductors, both ohmic and Schottky, and there have been a number of people that have looked at those technologies. These are dominated by fundamental studies of Schottky contacts, with the mechanism of ohmic contact formation receiving a little bit less fundamental attention in my opinion. What's your opinion?

PEARTON: Well, I first started doing contacts when I came in '92 to a conference in Fort Lauderdale, Florida run by some guys called Paul Holloway and Tim Anderson. The first thing I realized was that I left New Jersey and the temperature in February was about 25ºF. It was gray and there was snow all over the place. I arrived in Fort Lauderdale and it was so bright I could hardly see. I'm thinking, "These guys are not as dumb as they look. Why am I in New Jersey when they're down here in this stuff?" So I went to that conference and there were a lot of interesting contacts and fundamental studies. We had an interest in contacts for different material systems at Bell Labs, and again predominantly exactly what you pointed out. The Schottky contacts on gallium arsenide were not studied that heavily because no matter what metal you put on the gallium arsenide, you got the same Schottky barrier. Then the ohmic contacts were kind of a disaster. They were using this alloyed germanium-nickel thing which had been around forever, and the only reason they used it was that it worked, but it was a disaster in terms of uniformity and reproducibility. So after being at the conference and seeing that yes, we should start measuring some fundamental things - like Fermi level pinning - effective cleaning we thought was going to be a big deal because the Schottky is in intimate contact with the surface. We had some work going on measuring surfaces prior to metallization, so we were using those on cleaning and other things. So really, our interest was to try to get more thoroughly stable ohmic contacts and to see if we could get Schottky contacts that actually followed the work fuction, not just the pin the Fermi level on the surface. So Paul Holloway knows about that [chuckles].

HOLLOWAY: A lot of people pay me for my breadth of knowledge! [Laughter] 

PEARTON: Yeah, that's just added to the list, Paul.

HOLLOWAY: You've been very prolific in terms of documenting your work with 34 book chapters published, 12 patents, and 1,300 journal articles. How do you remain so productive?

PEARTON: Well, you know, I think my adviser in Australia was the originator of that, because one time, what he did was he wrote down a kind of a summary of experiments that he could be doing. So he was - In fact, this is Alistair Tavendale who passed away. So one time I saw that he was working on this file, and he had written down more than 110 potential papers that he could write if he could just do the experiments for them, and amazingly detailed. I mean, he knew if he just did this experiment and got this figure… So that kind of struck me, and then he and I - he was my adviser so we wrote together a lot, so we were fairly productive getting papers out. Then that led me to get to Berkeley, and then I was pretty productive at Berkeley. So that led me to get to Bell Labs. And then Bell Labs was always a volatile place - you were always thinking of leaving, and if you're going to leave, you've got to have a track record just like points on the board. So I always made it a point of writing up what I had, and that wasn't always true at Bell Labs. You've got people saying, "Oh, we don't need to write that up. That's trivial," or whatever. But at the end of the year when their annual reports were due, they'd be running over to me saying, "We published that paper, right? Give me a list of all the things that I was on." So I was from day one, it seemed that publishing papers was a way of - it's like homeruns for baseball: they can't take them away from you. I've also never had difficulty writing papers. It just seemed like it was fairly easy for me to do that, and there are so many journals, they all want content. I've been very fortunate. I've collaborated with a lot of people.

HOLLOWAY: Yeah, you're very interactive.

PEARTON: Right. So that's I think what makes it easy. When I was at Bell Labs, for example, in the group that I was in, we had an MBE system, an MOCVD system, a gas-source MBE system, and an MOMBE system. So they could grow samples by four different methods, and then we would wet etch them, dry etch them, put contacts on them, make devices, test the devices, irradiate the devices, anneal the devices, and so on. So what you're looking at is 4x8x5x6x something, so if you just had the time to write the papers, you could generate a tremendous number of them. Bell Labs was very interactive. Now I have the students write the papers, so it's easier for me.

HOLLOWAY: Sometimes that's easier.

PEARTON: Sometimes it's easier; sometimes they would be struggling.. But I think it's just something that I always found pretty easy.

HOLLOWAY: Yeah. Well, we've covered a lot of territory. I don't know if there are any other subjects you'd like to add to the interview.

PEARTON: Well, I think that the idea of being a professor has grown on me over the years. When I first came here - I remember I came here to give a talk in 1987. Kevin Jones had just started here, and I met with Dr. Abbaschian just prior to my talk and he said, "Well, we have some faculty positions open here." I said, "The day I come to a university is the day I'm ready to retire, because you guys have got nothing to do." So they were famous last words. It was about six or seven years later I was down here. So I think the university professor has a lot to offer, and I think seeing the students go out and get good jobs and kind of progress with their lives gives you a feeling in the university that you're leaving kind of a legacy, whereas in a company, you're only as good as what you did last week. So there are plusses and minuses. As you alluded to, it's a somewhat slower progress technically, but it's compensated by these other aspects.

HOLLOWAY: What do you see for your future?

PEARTON: Well, since my wife is now entrenched in the administration here, I don't see us leaving. I wouldn't want to leave Florida, to be honest, because I just like the kind of lifestyle.

HOLLOWAY: What about the projects that you see or activities?

PEARTON: Yeah, the projects I see - we're working on a lot of new sensor stuff that's particularly for detecting breast cancer using saliva or breath condensate, and we're using semiconductor sensors to detect all kinds of things and then integrating those with wireless transmission of the data. So in theory, you could have a hand-held sensor you breathe into that would send that data into a doctor's office in your electronic account there. The problem you have right now for almost any test at a doctor's office is you go there, do one test, and if it's a false positive, there's a lot of expense and emotional aggravation. If you could breathe into something remotely and do that four or five days in a row, it would eliminate pretty much false positives, and only if the thing was really consistently showing a positive would you need to go see a doctor. So it turns out there are lots of potential there for that kind of sensors, if you need a sensor that's specific to what you're looking for. So we have some projects right now where we collaborate with the medical school, and that's been real exciting for us. So again, it's only possible because we have a good medical school here, and it's exciting to us because it involves surface science and measuring those small quantities, and we get to work with chemists and doctors, and they all bring something different to the table. So it's fun. I think that's a good area.

HOLLOWAY: I know you're working on zinc oxide and transparent electronics. What do you see as the future in that area?

PEARTON: Well, we have made zinc oxide LEDs, and I think they have a very dim future because we can't seem to make them work. [Laughter] 

HOLLOWAY: It's not very bright.

PEARTON: Not very bright. The p-type doping is a real problem, much worse than gallium nitride. So that I don't think is going to work. And the zinc oxide as a sensor material I think is also shaky because the surface is so sensitive. As sensors, there's a possibility. Some sensors would be fine. I think that transparent thin film transistors look interesting because you can grow amorphous zinc oxide or indium zinc oxide or indium gallium zinc oxide that's got a room temperature mobility of 20 cm2/V-sec. We've made transparent thin film transistors. We're trying to make circuits out of them. We're trying to integrate the displays. So that's interesting work. But again, the surface is not stable, so we need to be working in that area. It's exciting. There's always a new project. The students kind of keep you young, because you could get jaded as a professor, but the students can kind of move things along and keep it interesting. So I'm excited about the projects here.

HOLLOWAY: Great. Well, let me close by congratulating you once again on the John Thornton Award. Well deserved, Steve.

PEARTON: Thank you very much, Paul.
 


return to top