Dr. Bortrum

06/01/2011

Off to a Shaky Start

Concerning the flooding, I can't help wondering if all that worldwide flooding isn't related to global warming and the resulting increased water content in the atmosphere. Along these lines, I felt an article that appeared on page 24 of the May 4 edition of the Star-Ledger truly should have been front page news. The article's headline was "Researchers forecast up to 5-foot rise in ocean levels by turn of century". The subject was a report from the Arctic Monitoring and Assessment Program of the 8-nation Arctic Council based on recent improved research and scientific papers on the melting of Arctic glaciers and ice caps. Greenland's huge ice sheet is included in these new studies. 

In 2007, the UN's expert panel on climate change projected a rise in the ocean levels by 7 to 23 inches. A rise of two feet was worrisome enough for low lying islands and some ocean front coastlines. But this latest reevaluation of the ice melting raises the projected rise in ocean levels to 35 to 63 inches by 2100!   A rise of five feet would be devastating for Florida, where my favorite vacation spot of Marco Island would be under water. Even New York and Boston, to take just a couple of examples, would suffer greatly. Those subways are likely to be flooded, just for starters.  

For me, global warming is a concept easy to understand, although complex to study and predict. On the other hand, longtime readers will know that my scientific hero is Einstein, whose theories are way beyond my feeble brain's capabilities to understand. A recent NASA press release, 11-134, on May 3, describes results from NASA's Gravity Probe B mission that confirm two of Einstein's space-time theories with exquisite precision. These are the warping of space and time around a gravitational body and the so-called "frame-dragging", the amount a spinning body drags space and time with it as it rotates. I won't attempt to elaborate on these findings but the developments related to Gravity Probe B, launched in 2004, have apparently contributed significantly to practical things such as GPS systems that, for example, allow planes to land unaided. On this Memorial Day, I might also note that Spirit, that plucky Mars rover, has died, with NASA finally giving up trying to bring it back to life. 

Well, back to my memoirs and my own life. In my last column, I took leave of NACA and Cleveland to move to New Jersey and Bell Labs in November of 1952. Before going into my Bell Labs career, I should note that of greater personal significance was the fact that shortly after settling down in new Jersey, we met a wonderful surgeon, Dr. Robert Hiatt, at Columbia Presbyterian Hospital in New York. Dr. Hiatt was the kind of doctor who inspired immediate confidence and he performed major surgery on our son Harry that corrected a serious problem present from birth. Both my wife and I would in our elderly years also undergo lifesaving surgeries at the same hospital. 

I should also mention that we picked a garden apartment complex in Plainfield, Leland Gardens as our first residence in New Jersey. At the time, polio was still something to be feared and indeed one of our neighbors in an adjoining apartment did contract the disease. Thankfully, Jonas Salk, who was at Pitt during my time there as a grad student, came up with his vaccine and we were among the first to be made immune to that dreaded scourge.  

OK, let's get back to Bell Labs. Some readers of these columns may know much of what comes next but bear with me. My immediate boss was Morgan Sparks, a great boss, especially compared to the one I had at NACA. Morgan, working with Gordon Teal, mentioned in my last column, were responsible for the first grown p-n junction transistor. On my first day the first person he introduced me to was William Shockley, later to share the Nobel Prize for the transistor. I had barely heard of the transistor and was more impressed with the fact that I had read a paper by Shockley and a fellow named Nix on order-disorder in alloys when I was working on my PhD at Pitt. In fact, one reference in my error-filled publication was to Nix and Shockley's paper.  

I soon found myself sitting in meetings with Shockley, Walter Brattain (to share the Nobel with Shockley and John Bardeen), Jim Early (later to become a key player in Fairchild Semiconductor) John Moll (later a professor of electrical engineering at Stanford), Ian Ross (later president of Bell Labs) and other semiconductor superstars talking about things that were about as understandable to me as Einstein's general relativity theory. When I was at Pitt I had a course in the basics of quantum mechanics. As far as I was concerned, this was an interesting field but not of any practical importance. To my amazement, these guys at Bell Labs were actually using quantum mechanics to make and study real devices. I remember being in a meeting where they were discussing a device they called a field effect transistor, which in one form or another is present by the zillions in today's phones, computers and the scads of other electronic products.  

There was also talk about such things as "deathnium", a strange impurity that made its way into transistors and would louse up the electronic properties of the devices. It turned out that one form of deathnium was just plain old copper, which one could pick up on door handles and be transferred to the germanium cr4ystals if you weren't careful. Copper diffused, traveled into the germanium, quickly compared to the normal impurities (dopants such as aluminum, arsenic, etc.) used to make the transistor structures. Another impurity that diffuses relatively rapidly in germanium and silicon is lithium and it was lithium that nearly got me fired from Bell Labs after my first year there. 

While I was totally in awe of all the talk about quantum mechanics and magical transistors, as a chemist the diffusion of impurities such as copper or lithium into germanium, then the material of choice for transistors, was something I could understand. Also, there was a theoretical fellow in another area, Howard Reiss, who was pointing out that the behavior of impurity elements in semiconductors like germanium was very similar to the behavior of salts dissolved in water. Sodium chloride, common salt, dissolves in water to form sodium ions (sodium gives up an electron) and chloride ions (chlorine picks up the electron). The impurity element arsenic, for example, "dissolves" in solid germanium where it gives up an electron and the arsenic atom becomes positively charged, akin to the sodium ion.  

Without going into detail, I embarked on a project to see how lithium would interact with other impurities in germanium. You may recall that in my previous work on electrochemical cells I had used molten salts of lithium as electrolytes. I figured I had some experience with lithium. However, working with lithium metal proved to be another deal. After spending some time working on the project, I decided that hey, this is not easy. Lithium is a very reactive metal and hard to handle and I was getting nowhere. Being very naive, I dropped the project without telling anyone and began another project on my own. I was, after all, in the Research Area at Bell Labs and had come from NACA, where we were free to do anything we wanted while waiting for our cyclotron to be built.  

Well, after a year or so, it was merit review time. Addison White, who was Morgan Sparks boss, called me in with a serious look on his face. Ad told me that they were very disappointed in my performance and that I was being put on probation. My cause could not have been helped by the fact that during that first year I had given a seminar on my work at Pitt and that I had later given another seminar in which I reported finding the error in the plotting of my data. Ad was in the front row at that second seminar and I noted a somber look on his face at the time. Decades later, at some sort of celebration, I saw Ad and mentioned that he had almost fired me in my first year. I was surprised that he remembered the incident quite clearly, saying that at Bell Labs they took firing someone quite seriously. Ironically, lithium almost got me fired; yet I spent the last half of my career at Bell Labs working on lithium batteries! I finally learned how to handle it. 

So, what saved my career at Bell Labs? I switched my attention from lithium to arsenic, one of the impurity elements used to dope germanium for transistors. Specifically, I decided to try to measure the vapor pressure of arsenic over germanium at different temperatures using a simple experimental technique - the so-called "dew point" approach. Weathermen and weatherwomen frequently mention the dew point, the temperature at which water vapor in the air condenses to form dew, liquid water. In my case, I built a furnace in which I could control the temperatures in two zones with a window to observe the cooler end of the furnace.. I sealed off arsenic and germanium under vacuum in a fused quartz tube. The idea was to heat the arsenic and germanium together at one end forming a liquid germanium-arsenic alloy in equilibrium with solid germanium. Then I would cool down the other end of the tube until the temperature matched the dew point of the arsenic vapor over the alloy. At this point arsenic should condense out and form a visible deposit. Knowing from the literature the vapor pressure of arsenic as a function of temperature, I would then calculate the pressure of arsenic over the alloy. If you don't follow this line of reasoning don't worry, the technique didn't work! 

I found out that arsenic vapor has a tendency to "supercool", something like water supercooling below the freezing point. I found in the literature that not only did arsenic have a low "sticking coefficient", i.e., it doesn't want to condense readily out of the vapor, but also arsenic vapor isn't just arsenic atoms but is a mixture of atoms and arsenic molecules comprised of either 2 or 4 arsenic atoms! Each, I presumed would have their own sticking coefficients. This was not good! 

What to do? I decided to invert the dew point technique by separating the arsenic and germanium at opposite ends of my sealed tubes and look at the germanium hot end of the tube as I raised the temperature of the arsenic end. Hopefully, when the arsenic pressure reached the proper value the germanium and arsenic would start to form a liquid alloy and I could see this through my window in the furnace. Well, this inverted dew point method seemed to work and the data were consistent over the range of temperature I studied. The treatment of the data was also more complicated because of the various arsenic species in the vapor. I wrote a Technical Memorandum (equivalent of a paper within Bell Labs) and I thought it was sort of a neat memo that I wrote. Well, shortly after the memo was distributed in July of 1954, Ad White called me into his office and told me I was off probation! My job was saved by arsenic. 

Next time I'll talk about settling in at Bell Labs and about the differences in lifestyles moving from the Midwest to a New York suburb. 

As I was about to post this column, I picked up my copy of "Heroes Among Us", a book about those who served in World War II from our small town of Mechanicsburg.   The book's author, John Ent, is a combat veteran of Korea and Vietnam who retired as a Lieutenant Colonel in the U.S. Army Infantry. Ent, with whom I played baseball and football on the field across the street from his house, is certainly a hero himself. He compiled this book as a tribute and memorial to those from Mechanicsburg High School who fought in that war and interviewed as many as possible of those who were still living (publication date 2004). There were thirty who paid the ultimate price of serving our country. I suspect that there were roughly that number of victims of Mr. bin Laden on 9/11 in the three or four towns comprising our local area here in New Jersey.