Crystals reflect the best of nature’s handiwork. With their atoms aligned in repeating 3D patterns, crystals can be as momentary as a snowflake or as common as the sodium chloride in table salt. They can sparkle on a finger, scatter rainbows across the room, or be grown on your kitchen table with a few ingredients from the hobby shop.
Some also possess unusual properties, such as quartz crystal’s ability to generate a tiny electrical current when pressure is applied. Known as the piezoelectric effect, this useful phenomenon helped inspire the rise of a global, multibillion dollar crystal growth industry.
Today, manmade crystals power an astonishing range of devices from the sensors that control electronic functions in cars to the semiconductors driving computers and smartphones. Discreetly hidden from view, industrial crystals form the backbone of our technology-based society.
Much of the credit for perfecting the underlying raw materials goes to the glittering mind of Kelvin Lynn, the crystal maker.
When not locked away in his office, this unassuming Washington State University professor can be found in the engineering hallways, bantering with students in his crystal growth program. Sometimes, just for fun, he’ll let them grow artificial rubies or sapphires in one of the nine furnaces that crank out a unique array of crystals in vacuums and at higher temperatures than any other institution in the world.
“It gives them experience and they all get good jobs in the industry,” says Lynn, Regents professor in physics and mechanical and materials engineering, and Boeing Chair of Advanced Materials at WSU’s Voiland College of Engineering and Architecture.
With an amiable, Burl Ives demeanor, the white-haired physicist started the program when he first arrived from Brookhaven National Lab in 1996. Getting acquainted with the Pacific Northwest, he learned that the region’s abundant, reliable supply of hydroelectric power helped make Washington a leader in crystal manufacturing. A large percentage of the world’s silicon and laser materials, for example, are produced in the area.
Hoping to give his students hands-on training, Lynn set about building the infrastructure for an academic program. His success was no small feat considering the enormous cost and energy requirements of growing crystals. The process itself can be long and tedious, the end product frustratingly fragile.
Today, after 20 years of effort, WSU is renowned for the precise engineering of a variety of valuable crystals including cadmium telluride (CdTe), popularly referred to as “CadTel.” These lead-colored, difficult-to-grow crystals are an industry favorite and WSU is one of the only universities actively developing them.
CadTel’s adaptable nature and unique electrical properties make it particularly attractive for use in solar energy and medical imaging. The crystals are exquisitely sensitive to radiation, paving the way for cheaper solar power as well as low-radiation dental X-rays, mammography, and CT scans.
The fortunate students who graduate from the crystal growth program each year carry their experience into top research and manufacturing positions across the nation. Waiting to take their place in a coveted mentorship with Lynn are new students from as far away as Iraq and India.
Lynn is indeed an accomplished, highly regarded scientist, but it wasn’t always this way. As a boy, his sights were set on testing the laws of society rather than the laws of physics.
Kelvin Lynn was born in Rapid City, South Dakota in 1948. Like a lot of kids during the Sputnik craze, he began building rockets with his brother. Since model kits were unavailable, the Lynn brothers scavenged raw components and concocted their own rocket fuel.
“We used saltpeter, gunpowder, stuff like that,” says Lynn. “It was fun and challenging—of course, there was something about the explosions too.” And their rockets flew great distances—one right through the front room window of a house miles away. “They knew immediately who it was,” he says. “Those Lynn kids!”
While the boys were busy with their adventures, however, trouble was brewing behind the scenes. A series of family problems erupted that quickly put an end to Lynn’s carefree existence. In the fallout, the brothers were left to fend for themselves during their teen years.
“I drank a lot,” Lynn says. “One time I got in a fight with a teacher. But I could still do well in certain classes in school. If I was interested in a class, I could do really well.”
And, if he didn’t like it, well, he just wouldn’t bother. As for homework—why waste his time on problems that thousands of students had already solved? School officials were at a loss as how to handle Lynn.
First, they wanted to put him in the special education classroom. A year later, they were ready to send him to military school. They also tried to advance him two grades in one year.
Yet a few teachers recognized something special in the troubled boy who, despite his behavior, showed a flair for math and science. They reached out to him and provided opportunities to help him find his way.
“It’s what saved me,” Lynn says.
One of those teachers, Mr. Pearson, taught high school chemistry.
“He was an incredibly good teacher at a time when I was starting to explore things academically,” says Lynn. “He encouraged me and let me work in the chemistry lab after hours. During that time, I realized there were problems in science no one had the answers to—things you could do that no one else could.”
That exciting insight lit up his whole life. Suddenly, Lynn saw science as a world of interesting puzzles to be solved—a passion that has endured through the years.
Sitting in his office today, Lynn no longer looks the part of a teenaged rebel. Yet his face grows boyishly animated—blue eyes
darting around the room—as his thoughts skip from antimatter to solar power to jaw-dropping medical technologies to collaborations with major industrial giants.
Through it all, Lynn makes it clear that teaching and interacting with good students are his top priorities, and something he genuinely enjoys.
Just as science saved his sanity and probably his hide, Lynn pays it forward by mentoring students from all over the world—training them, testing them, working them hard until, he says, “If I do my job right, they’ll think I’m worthless.”
At a small research company near Boston, Amlan Datta ’13 PhD painstakingly grows CadTel and other crystals in their simplest forms. Then, he finds ways to improve them.
Datta was hired as a scientist at CapeSym, Inc. one week after he graduated from the WSU crystal growth program.
“It’s an exciting field,” says Datta. “We develop the core crystal material that is used in a huge range of applications from medical imaging, homeland security, nuclear, and astrophysics research.” Like the foundation of a house, he says quality core material is essential for manufacturing reliable instruments and systems.
Datta remembers Lynn as a great mentor who took good care of his students.
“Kelvin was very involved,” he says. “Because we were students, we got tired and wanted to go home but he’d say, ‘Let’s talk some more.’ It was amazing as some PhD students never talk to their advisors for months.”
That level of involvement paid off for Datta who now develops innovative crystal materials such as CadZincTel (CZT). Used as radiation detectors for medical imaging, CZT crystals give a very precise, detailed picture with less radiation.
“It is possible to see a tumor only a couple millimeters wide,” he says.
A few companies already have CZT products on the market. Datta says Gamma Medica, for example, makes a system called LumaGem for molecular breast imaging (MBI.) A Mayo Clinic study in 2015 showed that MBI provided superior imaging and low radiation exposure for women with dense breast tissue, which can affect up to 40 percent of the female population.
High-resolution, lower-radiation CT scanners are also in development by other manufacturers.
Sixty miles north in New Hampshire, fellow alumnus Drew Haven ’13 PhD grows industrial sapphires as a research scientist for Saint-Gobain.
“Kelvin was a great advisor. He provided direction but at the same time let me figure things out by myself which was really helpful in the work I’m doing now,” he says.
Haven develops sapphires for military applications such as infrared windows in the new F-35 Joint Strike Fighter jet scheduled for deployment by the Air Force, Navy, and Marines. The sapphire windows protect infrared tracking sensors within the aircraft.
He is also involved in the production of bullet-resistant windows for large military ground vehicles.
“These protective windows are usually made of many layers of glass and are very thick and heavy,” says Haven. “Sapphire is significantly harder and stronger than glass, so we’re using sapphire as the outside face that would be hit by a bullet. It allows us to make the window much thinner and lighter than the standard
The Voiland College of Engineering and Architecture sprawls over the west end of campus in a massive complex of hallways, cargo elevators, and laboratories. Scattered throughout this maze are the specialized crystal growth furnaces hand-built by Lynn and his graduate students.
The superheated Czochralski furnace, for one, turns out a sparkling array of laser crystals as well as industrial rubies and sapphires similar to those Haven uses. The Czochralski has the singular ability to grow at different pressures or even in a vacuum.
Then there are the assorted Bridgman furnaces, adapted for growing piezoelectric and semiconductor crystals. The largest of these, the high-pressure Bridgmans, are tucked away in the corner of a cavernous old building. The giant contraptions once produced piezoelectric crystals for use in Navy sonar and medical ultrasound machines manufactured by Philips, Inc.
Today, these furnaces are being remodeled for the development of thin-film CadTel solar material under a $1.1 million Department of Defense SunShot Initiative award. WSU will join forces with the National Renewable Energy Laboratory (NREL) and Nious Technologies, Inc. to enhance and refine the CadTel growth process.
The goal is to make solar power more efficient and affordable while boosting U.S. competitiveness. Ninety percent of solar cells are currently made of silicon and manufactured in China.
CadTel offers a low-cost alternative. The cells are cheaper to produce than silicon and don’t degrade as fast. They also perform better in hot, humid weather and under low light.
Unfortunately, CadTel had a problem that stumped scientists for years. It was less efficient than silicon for converting sunlight into electricity. But that was about to change.
Not far from the high-pressure Bridgmans, postdoctoral researcher Santosh Swain grows CadTel crystals in a modified vertical Bridgman furnace. Swain came to WSU from India in 2005. Last year, he and Lynn made solar power history.
Through a slight twist in the crystal growth process, Swain, along with researchers from NREL and the University of Tennessee, increased the maximum voltage of CadTel solar cells to more than one volt, boosting their efficiency and breaking a decades-long barrier.
For over 30 years, the maximum voltage had been stuck at 900 millivolts, frustrating hopes for widespread use of thin-film solar cells. The discovery was published in Nature Energy in February 2016 and culminated in the SunShot award.
The trick was to add a little phosphorus during the crystal growth process.
“It’s a significant milestone—one that brings CadTel closer to becoming a competitive energy source,” says Lynn. “Others have tried but they didn’t have the control and purity that we have. WSU is known for growing really high quality crystals. You have to control every step.”
Swain dons blue rubber gloves and carefully lifts a circle of polished CadTel crystal. Tilting it in the light, the wafer shines like a silver mirror.
“In terms of the synthesis process, there is no difference between solar and medical grade CadTel crystals,” he says. “The difference is what we add when we grow them. Depending on the properties we want, we add a tiny amount of foreign atoms in a process called doping. In this way, we fine tune the electrical characteristics of the crystal and make it suitable for different applications.”
For example, crystals destined for medical imaging are doped with indium. Solar grade crystals are doped with phosphorus or arsenic.
To demonstrate, Swain ushers me to a small room housing the vertical Bridgman furnace—a silver stovepipe-looking affair bristling with wires and hoses. Here crystals are grown in a process called the melt growth technique.
In effect, the raw crystal material is liquified layer by layer as it rises through a series of heaters set at 1,200 degrees Celsius. The heaters are then cooled from the bottom up, allowing the material to crystallize vertically.
Swain shows me some of the finished product—miniature CadTel solar cells used for testing purposes. A full-size solar panel made by First Solar, the largest U.S. manufacturer of CadTel solar cells, is propped against the wall. It looks like a big black rectangle.
“They start with a sheet of glass and then deposit roughly 4 microns of CadTel film on top of it,” he explains. “Silicon, in comparison, requires hundreds of microns of material.”
The panel absorbs 99 percent of visible light which is converted into electricity that can be stored in a battery, used to power an appliance, or routed into the electrical grid. Though CadTel solar is currently used in commercial markets, Swain says it’s not quite ready for residential use.
Tawfeeq Al-Hamdi is trying to speed that along. As a faculty member in the College of Engineering at Al-Mustansiriya University in Baghdad, Al-Hamdi was offered a chance to pursue a doctoral degree at WSU in 2014 and recently began working with Lynn on a CadTel solar project.
Al-Hamdi is among more than 300 graduate students in the United States who are taking part in an Iraqi government-sponsored scholarship program aimed at rebuilding their country’s scientific community.
During the Gulf Wars, he says the United Nations Security Council imposed sanctions on Iraq that made it difficult to get the publications and resources necessary to conduct quality research. They’re now rushing to catch up.
Tall and well-spoken, Al-Hamdi says, “Coming to WSU offers a good chance to see how professors in the U.S. teach their students. We also have a chance to see procedures for advanced research here.”
Al-Hamdi is learning to build a multilayered CadTel solar cell and will study its performance under different temperatures. Solar cells are less efficient in high heat, so he hopes to stabilize the cell by adding a type of “phase-change” material often used in silicon.
He says Iraq’s year-round sunshine makes it a good candidate for solar energy. As a clean and competitive source of electricity, it could also reduce the air pollution lingering in Baghdad and throughout the Middle East.
Even as Al-Hamdi smiles, the strain of relentless war and terrorism shows in his eyes—Al-Qaeda and ISIS are all too real. But the skills and education he’s gaining can help Iraq recover, and he’s thankful for the opportunity.
Upon entering Lynn’s office, the first thing you notice are the NASA posters. Then, the bumper sticker: “Positrons are another matter.” On his desk, sunlight plays up a sampling of crystals—lavender, yellow, green, and deep red.
More than just a pretty display, the crystals represent a crucial step in Lynn’s passion to harness the power of antimatter. He’d originally come to WSU to kickstart an antimatter research program with the goal of developing fuel for space travel. As fate would have it, the project stalled.
He was having trouble detecting the gamma rays that are emitted when antimatter particles, called positrons, collide with matter and annihilate. CadTel could solve the problem but the rare material was extremely expensive and difficult to come by.
Lynn knew a bit about crystals and decided to try growing CadTel himself. With typical intensity, he not only succeeded but also managed to improve the crystal’s purity and yield.
It wasn’t long before major industry leaders came knocking at Lynn’s door, anxious to collaborate and hungry for the high-quality crystals he could produce.
It’s a story he wants to continue. “We need to keep developing novel materials and make them better, more efficient, and less expensive,” Lynn says. “Crystal growth is a key economic driver in the U.S. But it’s very hard—you have to be very patient to grow crystals.”
Though he doesn’t talk about it much, Lynn is grateful to that small South Dakota town where people took the time and gave him that second, third, and fourth chance.
“They kind of turned a blind eye,” he says, thinking back. “I probably wouldn’t have made it if it happened today. After living in New York, I saw a lot of the young people there…if they got in trouble, they didn’t often get a second chance.”
He pauses, looking out the window for a long moment.
“It paid off,” he says.
The matter of antimatter — Inside the W. M. Keck Antimatter Laboratory at WSU, Kelvin Lynn and Marc Weber build traps for positrons.