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11/29/2011
Ups and Downs
CHAPTER 16 - The Light Gets Brighter
After Hurricane Irene and our October snowstorm, the weather gods have relented and here in New Jersey we've had a relatively disaster-free November. Even so, work remains to clean up debris and remove hanging broken branches, including one large branch I just spotted in perched precariously high up in our lone remaining tall tree in our front yard. Our tree guys took down our split cherry tree that brought down our power and cable lines. My concerns about our storm related problems has kept me from writing about a bunch of interesting scientific stuff that's been making headlines; I almost wish I were still writing once-a-week columns.
For example, in my former field of lithium batteries, Igor Kovalenko, Bogdan Zdyrko, Alexandre Magasinski, Benjamin Hertzberg, Zoran Milicev, Ruslan Burtovyy, Igor Luzinov and Gleb Yushin published a paper in the October 7 issue of Science on the use of a compound derived from brown algae to increase the performance of lithium-ion batteries. Why did I mention the names of all 8 of the authors? When I saw these names I assumed that the paper came from Russia, some other Eastern European country or perhaps Israel. I was shocked when I found the authors were at Georgia Tech and Clemson! Lithium batteries were in the headlines last week with reports of a fire in the Chevy Volt, powered by lithium-ion batteries.
Stifling any urge to resume a once-a-week column, let's return to my memoirs and see how my own entry into the lithium battery field came about. In last month's column, I found that developing a product was not as easy a task as many of us in the research area of Bell Labs had imagined. Notably, it took a long time before my development group managed to make gallium phosphide (GaP) material for LEDs with the 2% efficiency figure we had achieved in our research effort. Fortunately, I attended an impressive thesis review of a prospective employee, Bob Saul, and hired him for my group. At about the same time, I also hired a young lady, Jolanta Armstrong, as his assistant. In those days there was still a degree of sexism; I recall my boss wondering if, being a gal, she could handle a wrench!
Along these lines, there was a very interesting article in a recent issue of American Heritage magazine about "computers" in World War II. These "computers" were actually women hired to come up with the mathematical tables used to calculate the trajectories of the shells fired by soldiers in the artillery and by bombardiers in calculating the trajectories of the bombs they were dropping. Some of these same women were also tapped to learn the inner workings of the first powerful electronic computer, the ENIAC, and indeed they became the first to actually program a computer. Prior to the announcement of the existence of this machine and its capabilities, pictures had been taken that included the women working with the ENIAC. Yet, when the press releases appeared, the women did not. They had been washed out of the photos! Computing was to be a man's game, with only the men left in the pictures.
But I digress. Back to Saul and Armstrong, who teamed up with Bill Hackett in the device area to publish a paper in 1969 on red LEDs with 7% efficiency, the world's brightest red LEDs at the time. They achieved this high efficiency by carefully adjusting the levels of the dopants used to make the p-n junctions and also by introducing certain heat treatments into the process. Meanwhile, my old colleagues in the research area were not idle. Carl Frosch was instrumental in finding that adding nitrogen to GaP resulted in green light being emitted and Ralph Logan and associates reported green LEDs with efficiencies of 0.6 percent, also in 1969. While that's over 10 times less than the 7 percent efficiencies of the red LEDs, the human eye is much more sensitive to green than to red light and the green LEDs appeared brighter than the much more efficient red LEDs.
In May of 1970, I got a chance to publicize our LED work when I gave an award address at a meeting of The Electrochemical Society (ECS) in Los Angeles. I was active in ECS for many years, giving talks, publishing papers and had served as a semiconductor divisional editor for the Journal of The Electrochemical Society. I was a member of the Electronics Division of the Society; this division was split into Semiconductor and Luminescence sections. When the division decided to set up an Electronics Division Award, I was chosen as the first recipient of the award. I'm reasonably certain that the award committee chose me because I was one of the few who had worked on both semiconductors and luminescence.
Preparing for the award address, I turned to Linc Derick, who enjoyed putting our LEDs to practical use. He had already made a couple of digital clocks with red LED displays and, for my talk, came up with a tiepin with flashing red and green LEDs. When I gave the talk, I had a 9-volt battery attached to a circuit board under my shirt. When I turned on the flashing LEDs at the end of my talk it created quite a stir in the audience. I don't know if that tiepin was the first, but I like to think that it was the precursor to the plethora of ornamental items incorporating LEDs today.
I suspect that talk in LA may have spurred an invitation to give an invited talk in 1971 that led to one of the weirdest and most interesting experiences in my scientific career. I was invited to give one of the opening lectures at a 3-day meeting in Grenoble, France; the meeting was held in March of 1971 and was titled "Seminaire sur la Cristallisation en Solution". The weirdness began before the meeting, which I recall as being originally scheduled for January. Only a couple of weeks before the scheduled date, I got word from France that the meeting had been postponed until March and the organizers assumed that would not be a problem. Fortunately, I had no scheduling conflicts and said it was OK. Before the meeting, I asked our travel department at Bell Labs to make reservations for me in Grenoble and they recommended the Ritz Hotel - sounded good to me! However, the Ritz was fully booked and I got a reservation at another hotel, whose name I've forgotten.
I arrived in Grenoble the day before the meeting and the next morning I was picked up at my hotel by a fellow assigned to be my host for the meeting. Normally, when giving a talk at a meeting, our usual practice at Bell Labs was to have a rehearsal and be critiqued by one's colleagues. However, in this case, I had no rehearsal and was not nearly as prepared as I should have been. I packed some 60 slides in my briefcase and, on the plane trip over, selected about 20 slides for my talk. So, my host got me to the meeting, where I found myself to be the only speaker who gave his talk in English! Everything was in French except when I spoke and when someone in the audience asked me a question. I only had a semester of French in college and my proficiency, or lack thereof, was illustrated a couple of days earlier. My trip to Grenoble took me first for an overnight stay in Geneva, where I had dinner in a restaurant where the menu was in French. I ordered an appetizer than turned out to be sweetbreads, a dish I only had experienced once or twice previously. I was sitting next to an African diplomat of some sort and he must have been surprised to see that my choice of entree, unintentionally of course, was also sweetbreads! (Having just Googled sweetbreads and being led to Wikipedia, I suspect I might have ordered ris de veau and ris d'agneau, both sweetbreads, one from a calf and one from a lamb.)
Well, I gave my talk in the morning using those 20 slides. Relieved that my stint was over, I returned to my seat, all set to learn a lot of French in the next couple of days. But wait, I was approached by the chairman of the meeting, who said that Professor So and So, who was scheduled the next day, could not make it and would I give a talk on the theory of crystal growth? Whoa! I pointed out that I was not a theoretician but, knowing I had 40 slides left, said I could talk on other aspects of crystal growth. So, the next day, I gave another lecture, using up about 20 slides. OK, I thought, now I can surely relax. But no, up comes the chairman, saying they would like me to give another talk the last day of the conference! By this time, I was slaphappy and thinking about how humorous this French approach was and agreed to another talk. The next day I used the last 20 slides in my third talk and gave a sigh of relief that at last I was finished.
Wrong! The final item scheduled for the meeting was a panel discussion. And guess what? I was the panel! As I recall, there was about a half hour of questions from the audience, most dealing with our work at Bell on LEDs. The meeting was over. My host took me to a bank where I was reimbursed for my expenses. He also explained the reason for the postponement of the meeting from January to March. It seems that I was being reimbursed with funds from the French version of our Atomic Energy Commission and they hadn't yet come through with the money in January! Oh, remember the Ritz Hotel? When I got home there was a letter from France that must have arrived shortly after I embarked on the trip. In the letter was a reservation for me at the Ritz Hotel! Yet nobody in Grenoble mentioned the fact that I was staying at another residence. C'est la vie.
Before leaving France, I might mention the entertainment portion of my stay in Grenoble. One night, my hosts took me to a movie. I thought this was a strange thing to suggest for a new visitor to Grenoble. However, before the movie began a figure appeared on the stage, eliciting a tremendous cheer from the audience. I learned it was a fellow by the name of Sylvain Soudan, a skier renowned for his exploits, which included skiing in the Himalayas, the subject of the movie. Apropos of the skiing theme, the next afternoon my host took me to Chamonix. We rode the gondola up the mountain where the Olympics had been held. I was quite relieved when we got back in the gondola for the ride down. I had visions of me slipping on the icy slopes and hurtling down the mountain to my demise.
The last night in Grenoble found me accompanying one of the organizers of the conference and his family to a hockey game. I'm not sure if this was the first hockey game played in Grenoble or just the first game for the family. In any case, I had quite a challenge trying to explain the game to the family, whose proficiency in English was just a tad better than mine in French. I had been part of a group at Bell Labs that shared a season ticket to the Rangers games in Madison Square Garden and remember at my first game being mystified by the cheers that erupted when a player shot the puck down to the other end of the rink when one of the Rangers players was in the penalty box. Try explaining this time-killing move to a family unfamiliar with the game and the English language.
Back at Bell Labs, although my group, notably Bob Saul and colleagues, had come up with the brightest red LEDs, there was trouble brewing. The physicists in our materials area and those in the device area were at odds on the theories of light production in the LEDs and there were overlapping and conflicting efforts involving members of my group and the device area. In addition, I had a new department head whose management style was, shall we say, not to my liking. In fact, I found myself almost every week on Mondays having migraine headaches, which I speculated were due to the tension of having to go back to work under stressful conditions.
This speculation was confirmed in 1972 when my boss called me in and told me that I was no longer a supervisor - I had been demoted! And who was to take my place? Bob Saul, whom I had hired and I was indeed touting him as management material! He did express his regrets that his advancement was at my expense. I was given a choice of staying in the same general area or finding another job at Bell Labs. Fortunately, I found a place in the Battery Development Department headed by Dave Feder, who, sadly, just passed away a couple of weeks ago.
Under Feder, I found a refreshing spirit of camaraderie in the Battery Department (even today, remaining members of that department get together once a month for pizza). My weekly migraines stopped immediately and I haven't had one since!! That's almost 40 years! Getting demoted was great. I would be working on lithium batteries with an Englishman, John Broadhead, a very energetic and enthusiastic fellow who was working on various compounds for use as cathode materials in these batteries. Although I wasn't happy to leave the world of LEDs, lithium batteries were beginning to find niches in medical applications (heart pacemakers) and in electronic devices. And now they're even powering electric vehicles, e.g., the Chevy Volt (was there a fire recently?).
I was very lucky that one of the cathode materials that Broadhead was studying was a compound called niobium diselenide, NbSe2, a layered compound in which he was incorporating iodine between the layers. The reaction generating the cell's voltage involved lithium being transported into the layers and reacting with the iodine. The NbSe2 formed tiny hexagonal crystals when selenium vapor reacted with thin sheets of niobium metal. These crystals more or less would lie down flat on the niobium metal sheets and my first job was to try to get them to stand up on the niobium so the lithium could more easily slip into the layered crystals. In a battery this could lead to higher current capability.
How lucky was I? When I tried growing the pesky little NbSe2 crystals, I noticed that, in the course of growing the crystals, an intermediate compound formed. This compound was in the form of hairy fibers, not hexagonal crystals. I gave some of this fibrous material, which I later showed to be niobium triselenide, NbSe3, to Broadhead and went on vacation. When I came back, I found Broadhead scratching his head, saying that when he constructed a cell with the fibrous material, he didn't have to add the iodine and the cell had an initial voltage of more than 2 volts. We had found a new cathode material. While I was on vacation, Broadhead had contacted another Bell Labs fellow in the research area, Frank Di Salvo, and a patent application was filed with all three names on it. At the time I hadn't met Frank. So, I was launched into a new career in the world of lithium. Ironically, you may remember I nearly got fired shortly after coming to Bell Labs when I decided I couldn't handle lithium! Now I was to spend almost 17 years working with that reactive element, and with that hairy niobium triselenide!
Next column, hopefully, will be posted on or about January 1, 2012. Have a happy holiday!
Allen F. Bortrum
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