Shuji Nakamura - Inventor of Blue Laser Diodes

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http://img50.exs.cx/img50/9331/shuji.jpg

Shuji Nakamura, working for a tiny company called Nichia Chemical Industries on an island off western Japan, single-handedly developed the first commercial blue and violet semiconductor lasers, using gallium-nitride technology. The achievement was one of the most important leaps in the design of solid-state lasers. The wavelength of blue light is about half that of typical infra-red semiconductor lasers found in CD players and laser printers. The use of blue lasers therefore allows manufacturers to triple or even quadruple the amount of data that can be stored on a CD. Blue lasers also endow laser printers with resolutions even better than they have today. Nine consumer-electronics firms have now agreed on a standard for a recordable DVD with a six-fold increase in storage capacity based on Dr Nakamura's blue-laser technology. When Dr Nakamura left Nichia Chemical for a chair at University of California, Santa Barbara, sales of blue LEDs (light-emitting diodes) and lasers were bringing the firm more than $200m a year.

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True Boo-Roo


A blue laser is the Holy Grail, the closest the semiconductor biz has to pure sex. A small, japanese chemical company has gotten there first...

By Bob Johnstone


The Japanese language has no exact word for the color blue. The term the Japanese use, ao, is ambiguous - best translated as blue-green. Ao has the connotations of immaturity and inexperience that the English word green has. When the Japanese wish to be exact - when describing the color of Siamese cats' eyes, for example - they will sometimes resort to the English word blue, which they pronounce "boo-roo."

There is a scientific reason for the ambiguity of blue. In the electromagnetic spectrum of visible light, which runs from 780 to 380 nanometers, from infrared to ultraviolet, green is said to end at a wavelength of around 500 nm, while blue does not begin until around 490 nm.

But gap or no gap, there was no mistaking the color of the light shining from the tiny device that Shuji Nakamura hooked up in his laboratory one day in January 1993. It was true boo-roo, spiking on the spectrometer at 450 nanometers. And not just blue, but bright blue - a candela's worth, to use the international unit for measuring luminous intensity - 100 times brighter than the feeble blue glow other devices emit.

In coming up with a bright-blue-light emitting diode, Nakamura - a lone researcher working at a small Japanese company called Nichia Chemical, which almost no one, even in Japan, had heard of - had scooped the world. He pulled off a coup that had eluded researchers at blue-chip US, European, and Japanese corporations for the past 25 years. At the same time, Nakamura's feat also won him pole position in the race for the great prize, what the electronics trade papers call "the Holy Grail," the closest the semiconductor biz comes to pure sex: a blue laser. For history shows that if you can persuade a material to emit light, you can usually make it lase, too.

Blue is the favorite color among people around the world. But for the electronics industry, blue light is attractive for two reasons. One is its short wavelength, which lets a blue laser resolve (read and write) more information than any other color except violet. The second is that blue light can be combined with red and green - the other primary colors of the light spectrum - to produce any other color, including white. Both capabilities have the potential to dramatically alter markets: short wavelength means multi-Gbyte optical discs that will replace compact discs and CD-ROMs. Full-color-light emitters mean a radically new type of lighting - the end of the light bulb.

Lasers and light emitters are both diodes, a type of semiconductor device. In their simplest form, these diodes consist of a sandwich of two layers of material. Each layer is mixed with impurities to give it opposite electrical properties, an excess of electrons or of positive charge-carriers called holes.

Passing a current through such a device forces the electrons and holes into the junction between the two layers. There, they pair off in a marriage they celebrate by emitting a photon - that is, light. The difference between a light-emitting diode - an LED - and a laser is that in the latter, the light is amplified in a cavity within the device. The ends of the cavity are mirrors, which reflect the photons back and forth, causing them to hit other electrons, stimulating the release of further photons and amplifying the light.

Laser folk like to think that their devices are more difficult to make than LEDs. For their part, LED people claim that building lasers is a piece of cake once you master light emitters. But the two devices are structurally quite similar. Both are made using the same sort of equipment, high-tech reaction chambers in which layers of material are laid down on heated wafers. To change from one type of device to the other, all you have to do is rewrite a few lines of the program that controls the growth of the layers, and - bingo!

The invention of a bright-blue-light emitter by an obscure researcher at an unknown Japanese company surprised everybody. Especially as Nichia Chemical is based on Shikoku, the smallest of the four main islands in the Japanese archipelago, a no-tech backwater best known for seaweed and sweet potatoes. It was as if a hot new microprocessor had been announced by an outfit hailing from Nova Scotia, say, or Puerto Rico.

So what is this outfit, anyway? Turns out that Nichia Chemical is Japan's largest independent manufacturer of phosphors, compounds coated on the inside of TV screens that emit colored light when zapped by electrons. By Japanese standards, Nichia is a brash young start-up. It was founded in 1956 by Nobuo Ogawa in his hometown of Anan. The day I went to visit Nichia, Chairman Ogawa, who is now 82, was away climbing mountains in the border country between Manchuria and North Korea.

So I asked his son, Eiji, who took over as president of the privately held firm in 1989, what distinguished Nichia from other Japanese firms.

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"We don't have any managers, no proper businessmen," he replied, "so half the time, everybody's just playing around. For us, making things is like our hobby." And when it comes to making things, Nichia prides itself on taking an unconventional approach. "Ever since we started, we've always had what Japanese people call a twisted navel, a hesomagari," Ogawa explained. "Which means that we are a bit perverse - we don't copy what other people do, we use a slightly different method."

With just 600 employees, Nichia Chemical is a small firm by Japanese standards. The company cannot expect to recruit many highfliers. Shuji Nakamura is an exception - a bright young man from a local university, Tokushima, with a mind of his own.

Before deciding to go for blue, Nakamura spent 10 years refining gallium metal and coating wafers for LED production. Though technically successful, both projects were commercial failures - the markets for such products were dominated by much bigger rivals selling similar products. Then, in 1988, the Ogawas gave Nakamura the freedom to decide what he wanted to do next. From his experience, he already knew that making blue was the big challenge. Gallium nitride, the material Nakamura uses to make blue diodes, was first developed by Jacques Pankove at RCA in 1969. But Pankove could not make suitable positive-type gallium nitride, and, predictably, his management told him that what the market needed was not another color but a cheaper LED. Over the next 25 years, many other people have tried to make blue diodes, without much success.

Nakamura chose to work on gallium nitride not because he was confident of success, but "because I had had the bitter experience that if you do the same as everyone else, when it comes to making products, you can't sell them. So I chose a material that almost no one else was working on ... and our chairman and president let me have the money I needed."

In the Japanese world view, hardware precedes software: build it, they believe, and consumers will come. The formula has worked well for them in the past - the transistor was an essential precursor to pocket-sized radios, the red LED for early calculators, and the laser for CD players. To be sure, the hardware-first formula also has its shortcomings - for example, the rise of computer networking, whose significance the Japanese so comprehensively failed to grasp, cannot be attributed to any single component.

But for Japanese electronics firms in late 1994, the anticipated availability of key devices like short wavelength lasers makes it possible to plot a path that extends to the end of the century.

The amount of digitized information that can be stored on a CD is a function of several factors. Of these, the most important is the size of the pits that do the storing on the disc - the smaller they are, the more you can store: a thinner beam of laser light is required to read them. Current CD players use infrared laser pickups with a wavelength of around 780 nm to pick up about 650 Mbytes of information on an average disc. On the way are videodisc players that companies like Sony, Philips, Matsushita, JVC, Sanyo, and Pioneer plan to launch in early 1996. They use a visible red (635 nm) laser, which lets them store at least five times more information, enough for a 135-minute movie.

Pundits are currently debating whether the picture quality of these new machines will indeed be good enough to supplant the established technologies - videotape and laser disc. When they are introduced around 1998, blue-laser-based players should settle the quality question once and for all. They will be able to store up to 10 times as much information, enough for high-definition digital video. "This is very important," says Kay Nishi, president of the leading Japanese software publisher, ASCII Corp. "High-definition video will be like CD was for audio."

There are serious numbers involved here. In 1992, the last year for which reliable figures are available, the Japanese produced just over •1 trillion (US$10 billion) worth of VCRs and videodisc and CD players. And while production has dropped in the consumer electronics industry since then, the huge rise in shipments of CD-ROM players could make up the difference. At the same time, in personal computers and consumer electronics, the proportion of the value represented by components has increased. So, in many ways, blue lasers are an attractive proposition for set makers and component vendors alike. Now all they have to do is build them.

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But blue lasers have been a bitch to build. Indeed, for a while back there in the '80s, it looked as if researchers would have to resort to some fancy footwork, pumping regular infrared laser light through special, nonlinear crystals that halved its wavelength. But this inelegant approach would never fit into the teeny-weeny dimensions that late-20th-century consumer electronics firms demand. (A semiconductor laser, as chip makers never tire of telling you, is no bigger than a grain of salt.) Then in 1991, a flurry of excitement arose in the Midwest, as researchers at 3M's St. Paul laboratories announced they had built a working blue laser out of a compound semiconductor material called zinc selenide.

But there were problems with the 3M approach. Their little dingus was not very efficient - to persuade the laser to produce light, you had to zap it with so much current that if you ran it at room temperature, it would melt down in a moment. The only way you could get the device to work was to chill it in liquid nitrogen. And even then it would manage only a few brief spurts of light before succumbing to what laser folk call "catastrophic optical damage" - going pffft, you might say.

This was unfortunate, but it was better than nothing, and companies like Sony, Philips, and Matsushita threw themselves into making zinc-selenide diodes work. Researchers reassured themselves with the knowledge that lasers had always been finicky to begin with. Given time and patience, though, you could usually train them to do what you wanted - produce continuous beams of light, at room temperature, for tens of thousands of hours.

And to be sure, some progress has been made toward this goal. Leading the way is Sony, the world's largest producer of lasers. Even before the 3M announcement, Sony had been working on zinc selenide; by summer 1993, the Japanese firm had come up with a blue laser that shone continuously, at room temperature, for - well, at the time, Sony wouldn't divulge for how long. The ugly truth of the matter, though, according to Yoshifumi Mori, Sony's director of laser research, was that the company's lasers would last only a few seconds before giving up the ghost. Today, more than a year later, the record for longevity in zinc-selenide lasers is just nine minutes. Undaunted,

Mori maintains that he is "very optimistic" about the prospects of extending the lifetime of the lasers to durations that are commercially significant.

Meanwhile, back in November 1993, Nichia announced its blue LED, promising at the same time that a blue laser was under development. Nichia's devices are made from an entirely different compound material, gallium nitride. The announcement caught the rest of the industry with its pants down. Gallium nitride had long been written off as fatally flawed. Making a diode requires both positive and negative types of material, and no one had been able to make positive-type gallium nitride.

Nakamura found a way to do the trick, and overnight, the blue diode business became a whole new ballgame. Sony responded to Nichia's challenge by producing a bright-green LED made of zinc selenide, more or less just to show that it could be done. (At room temperature, green - at 512 nm - is about the best that zinc selenide can do: conventional green LEDs are not very bright and tend have a yellowish hue.) Nakamura met the challenge with a green LED of his own. Then he upped the ante by threatening to produce a violet laser, which has an even shorter wavelength than blue.

But while the race to build the first good-enough-for-commercial-use blue laser enters a new phase, Nichia has begun mass-producing its blue LED. Initial customers are makers of electronic billboards and other types of outdoor displays, including traffic lights. Nonblue LEDs - that is, red, green, and yellow ones - are already ubiquitous. Look around and you can probably spot dozens of the little buggers - including the off/on indicators on your computer, the lamps on your telephone keys, and numeric displays on your stereo. And there are plenty of LEDs around that you can't see - infrared emitters that control your TV, detect the presence of a floppy in your disk drive, or isolate the microcontroller from the motor in your air conditioner. LED makers - Sharp, Toshiba, Matsushita, and Hewlett-Packard are the big guys - crank out hundreds of millions of the tiny chips every month.

HP's George Craford - whom some consider the world's foremost expert on LEDs and who is the inventor of one of the most commonly used visible LED process technologies - estimates that at least 20 billion devices are made annually, and he admits that he may be off by a factor of two.

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This is chicken feed compared to what's coming. LEDs are extremely small, highly efficient, almost unbreakable, and very long-lasting. Everything, in short, that conventional, tungsten-filament lights are not.

As far back as the 1950s, even before the first practical LEDs were produced, scientists understood that if a semiconductor diode could be made to produce usable quantities of visible light, then they would have a kind of ideal lamp. In terms of conversion efficiency, of economic use of power, of longevity, and of size and weight, such a lamp would be to conventional tungsten lamps what the transistor was to vacuum tubes.

The LED can thus be seen as another element in the momentous, late-20th-century shift from fat to flat - from the gross bulbous objects made of evacuated glass and hot metal to the nanoscale thin-films of the solid-state microcosm. With Nichia selling blue LEDs to customers in significant volume, that vision is finally at hand. George Craford explained: "Now that you're getting to real bright devices in the red and yellow, and now that this thing has been done by the Nichia group in the blue, which should also work in the green to very high performance levels, there's no reason at all that you can't mix these and do white light. Fundamentally, the LED is the most efficient sort of light source you can have.

"There's no reason you can't replace tungsten lamps in a wide variety of applications with LEDs. I think LEDs are going to get to the point where they are substantially brighter than incandescents and will compete with fluorescents. They will have all kinds of advantages and will replace a lot of the lighting market. I don't know how long it'll take, but I think it will happen."

Craford's view may sound extreme, but it is shared by LED makers. For example, as Toru Teshima, former president of Stantely Electric, a leading maker of automotive lights, explained, "Something with such good reliability and long life is bound to become popular. Though high-brightness LEDs are still somewhat expensive (in comparison with tungsten filament bulbs, for instance) if you consider that they'll last a lifetime, they're really cheap.

One place where you can already see the great fat-to-flat shift taking place is out on the highway. High-mount center brake lights on cars are increasingly made from arrays of bright red LEDs. Not only do these lights weigh less, use less energy, and need no maintenance - they are also safer because they turn on more quickly than tungsten bulbs. At 60 mph, this earlier warning signal gains you about 4 yards of extra braking distance. And there are styling benefits, too. Auto designers are currently restricted to bulky, square-shaped light assemblies. But LEDs allow you to do long strips that can fit into the likes of spoilers. And since LEDs are less than an inch thick, they can be attached directly to a car's body panels and wrapped around curved surfaces. Some analysts suggest that within 10 years, LEDs will have replaced all the exterior lamps on cars except the headlights.

Now that LED makers can emit bright blue as well as red and orange, the fastest growing market for LEDs is outdoor signs and display boards. In the United States, LED signs like the ones you see at airport gates tend to be all red. To see the finest examples of this flourishing subgenre, you have to travel to Asia, and preferably to Japan, where LED signs can be seen everywhere. At ordinary train stations, LED sign boards consisting of mosaics of red, green, and orange dots (derived by turning on red and green simultaneously) keep you posted of the times of the next trains, their destinations, whether they are expresses or locals, when they are about to arrive, and so on. Inside subway trains, programmable LED signs are beginning to replace paper advertisements (which still have to be changed by hand, a labor-intensive job that young Japanese are increasingly reluctant to perform).

Indeed, programmable LED signs have become so prevalent in Japan that they now represent a kind of highly visible public information infrastructure. With the arrival of the blue LED, this infrastructure can be expected to extend still further because it will enable head-on competition with full-color display signs based on existing technologies.

And we're not just talking billboards and traffic lights.

Imagine the future of pachinko parlors, Japan's ubiquitous, guilded palaces of venality where off-duty salarimen repair to seek oblivion. Today, these dens of pinball-machines-for-gambling-adults animate Tokyo nights with screaming neon lights.


But the craftsmen who bend and install these neon tubes are gradually dying out, and in their wake lies a void ready to be filled by LEDs, whose designs present no end of possibilities in the hands of geeks fiddling with software. In the future, how many advertisers will scramble to insinuate their messages into the blinking world of pachinko parlors, or shopping malls, or even public squares?

Indeed, watch Japan's pachinko parlors, for they are the thin edge of a wedge that will change the way we see the world: those places now filled with light will someday be filled with information.

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http://www.japaninc.net/article.php?articleID=53

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At the Gorham/Intertech Conference on Compound Semiconductors held in San Diego March 1-3,'99 a half-day workshop called "Nitride Appreciation 101", was presented by Shuji Nakamura of Nichia Chemical, Robert Karlicek of Emcore Corp, and Steven Den Baars of UCSB as featured speakers. Karlicek represented Emcore , the leading U.S. manufacturer of equipment for epitaxial processing, DenBaars had just taken leave from UCSB's Nitride Labs to man a start-up company making GaN devices.
Karlicek gave a history of compound semiconductor development, DenBaars talked about the markets they were opening. Nakamura talked about the blue laser.

"Compound Semiconductors pick up where silicon leaves off"

The advantage of electronic devices made with wide bandgap materials (compound semiconductors like silicon carbide and gallium nitride) lies in their unique properties that allow faster switching than devices made with silicon chips.
SiC transistors, used for high power amplifiers, show ten times the power of silicon transistors, with 10 x the voltage capacity, 100 x the radiation resistance, and the ability to work at temperatures above 600? where most circuit boards would be turned to ash, giving off only 1/5 of the heat load. With
these characteristics, two markets emerge, said DenBaars: one for optoelectronic products - blue, green, white light emitters, solid state lighting and blue lasers for DVD and display; another for electronic applications that include high power microwave wireless and satellite communications and radar, and high power and temperature applications for power switching and combustion control.

Nakamura talked about using compound semiconductors (GaN and InGaN) to make blue LEDs and blue lasers, and their "huge impact on displays, optical communications, DVDs, laser printers."
Nakamura came from Nichia, a small chemical company in Japan. Competing with some of the largest R&D labs in Japan, he alone succeeded in making the first blue LED and blue laser with long lifetimes.

"Gallium, a product of the smelting of metals, notably aluminum and zinc, is rarer than gold"

Over the three day conference, speakers from universities, the DoD, semiconductor, telecom and satellite companies, paid homage to Nakamura's achievements, even while promoting development of one of the alternative compounds (Zinc\Selenide) to his choice of Gallium Nitride.
In an earlier interview by Frederick Su for SPIE, Nakamura was asked why he chose hard, intractable GaN for the blue LED.
"At that time in 1988, three materials were known for blue emission ñ SiC, ZnSe and GaN. (Most people) Öwere using ZnSe Öbut from my experience I learned to dislike competition and selected GaN instead of ZnSeÖthe important thing for me Ö was that no one else was working on it."

Contrasting with silicon, wide bandgap semiconducting compounds consisting of one element from the third column of the periodic table and one from the fifth (3-5 compounds), forward biased p-n junctions, are efficient converters of electrical energy to light.
However, processing of these 3-5 substances is far more difficult than the processing of silicon, and, until the early '70s, manufacturing methods were not available Since then light emitting diodes (LEDs) began to appear on the market whose optical output, reliability, and range of colors have steadily risen.
But until recently, no efficient bright blue LED was available. Without blue, displays using LED clusters and
projection displays using solid state lasers based on LEDs, could not achieve a satisfactory white, and scenes displayed were not lifelike.

Today blue LEDs are used in large area multi-colored displays, LCD backlights and laser printers, long lived and rugged auto and traffic lights, and in optical storage where blue lasers increase by more than three times the density of information stored on optical discs.
"Now, with a red laser diode, 4.7 gigabytes of data per side can be stored on a DVD (digital versatile disk); with a blue laser's shorter wavelength ñ meaning light can be focused more sharply - you can store 15 gigabytes per side." (Nakamura)

"The basic problem limiting InGaN device development was the lack of a suitable substrate material."

The key stumbling block in fabricating GaN based devices lies in making a satisfactory film. GaN, a very strong stable compound, must be grown epitaxially on a substrate.
But the customary techniques for growing thin films - by liquid or vapor phase epitaxy ñ do not work.
GaN can't be evaporated except at temperatures close to the temperature of the sun, can't be liquified, and does not dissolve in any known solvent. For crystals, it can only be grown "under practically volcanic conditions at temperatures of about 4500?, and at 60,000 times the atmospheric pressure at the earth's surface." (J. Harris/Stanford).

Therefore the predominant method for growing thin GaN film has been with Metallo-Organic Chemical Vapor Deposition (MOCVD), growing the thin GaN film on the surface of a (very hot) substrate. (Molecular Beam Epitaxy has been making inroads recently too.)

Since some steps for making the thin layers proceed at temperatures between 1000 and 1100 degrees C. the choice of substrates lies essentially between silicon carbide (SiC, or carborundum) and sapphire. Because of the exorbitant cost of SiC, most work has been done using sapphire, though sapphire's lattice dimension is a poor fit to that of GaN, and a great many dislocations are formed in the film.

"The crystal quality of GaN growth on sapphire was terrible," says Nakamura.
In addition there are problems with the chemistry of the metallo-organic compounds and the ammonia used as sources of the metals and nitrogen.
Nevertheless, starting in '88, Nakamura began the work to make blue LEDs. By 1995 his blue LEDs were running for 10,000 to 100,000 hours.
"Finally the successful growth on non- conducting, transparent sapphire by Nakamura et al, enabled LED development."(M. Peanasky, HP)

Starting with Nichia, the "blue laser club" has now increased to six + members, Hewlett Packard, Cree, Toyoda-Gosei, Sony, Panasonic, Samsung.
Key to his successes were the ingenious means Nakamura found to mitigate GaN problems.
In his talk he described how he obtained improved GaN layers by starting with very small, separated posts of GaN, then growing the crystals laterally rather than vertically, so the GaN formed on the posts rather than on the substrate ñ reducing the number of dislocations or faults, that sap at the fluorescence.

Later, by alloying GaN with Indium Nitride (InN), forming InGaN (Ingan), Nakamura obtained much greater efficency and brightness and could shift the color from the near ultra-violet all the way to amber.
Having achieved lasing from blue/green to amber, Nakamura hopes to make red also.

However, Nakamura never revealed how he got around the significant problem of making good ohmic contacts. A good guess for the disparity between Nakamura's achievement in lifetime, vs his competitors', is the discovery of solutions to the contact problem between materials.
Finding a way of forming effective, reliable contacts between compound semiconductors and the materials of their circuits, determines if a device can be made. Engineers have tried co-deposition during growth of the 3-5 film itself, and ion implantation with mixed successes. Ohmic contacts remains a problem for the nitrides (and diamond), that Nakamura has conquered.

Nakamura's blue and green GaN based LED's are now brighter than any available red LED. Embedding a blue LED in a yellow phosphor yields output of a broadband white, that can be used for room illumination, or a bright backlight for a liquid crystal display.
Thus Nakamura showed us that LEDs had caught up to and passed in efficiency all other means of converting electricity to light, except for fluorescent lights.



Although weak emission of blue light from GaN had been observed at RCA Labs in the early seventies, no notable progress was made for the next decade. In the 80's Dr. Akasaki at Nogoya U. added a thin layer of GaN grown in a low temperature (a "buffer" or "nucleation" layer) before adding the much thicker working layer at high temperature. Akasaki succeeded in greatly reducing the density of dislocations. He also made the first p-type GaN.

In North Carolina, Cree Corp. demonstrated a blue LED in 1988, but did not market it, following it in '90 with a LED made of silicon carbide, still relatively dim.
Starting in 1991, II-VI band blue diodes were developed by 3M, Sony and others, but they were plagued with very short lifetimes.
The first commercial blue LED was marketed in 1993 by Nichia, made by Nakamura. In 1995 Nichia introduced a green LED and demonstrated a pulsed blue laser. Nichia's blue laser appeared on the market in 1999, and a laboratory life test has logged 10,000 hours without failure, one hundred times longer life than has been reported anywhere else. Operating voltage has been reduced from 30 to 5vs.
This spring, a violet laser diode began shipping.
All of these devices were demonstrated to us, and pictures were shown of large spectacular LED displays around the world.

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http://www.eurekalert.org/pub_releases/2002-04/uocs-jga040102.php

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"The Book"
obviously a working title only... current suggested title: "Firefly"

Jo Ann McDonald's current nonfiction project covering the colorful history of the wide bandgaps

Preliminary draft flow, for the eyes of selected editors and principals referred to in the story. All other read at their own risk!

And... it has come to our attention that since the original Feb. posting of this, Google searches have picked us up when one enters the name "Shuji Nakamura". So FYI... Jo Ann McDonald is a 35 year veteran advanced technology journalist the founding editor of CompoundSemi News and LIGHTimes, and authors the popular "McDonald Report" read by an international audience. Refer to her bio for more details, and you can contact her directly at Legacy Ranch at tel: +1 325-463-5345.

Note: This is a VERY preliminary prologue. Chapter 1 is written and will also be posted soon. "The Book" includes "The Russian Connection" and there is a great deal on industry contributions by Cree, Nichia, Emcore, and Aixtron, especially during the 1980s and 1990s. Blanks indicate dates and accurate names/places which must still be verified off the author's very dusty library (opening that closet door is still a challenge)

All work posted copyrighted 2004 by The Legacy Company (and my copyright lawyer is one tough guy. Don't mess with us)

Jo Ann

Prologue

Flying from the ranch in Texas back in 199x to my native land of the San Francisco Bay Area to cover the annual IEDM (International Electron Device) meeting), I reminded myself why I did these things. "For $1 per word from my British publishers, that's why," I muttered to myself. That and a possible byline in one of the many mainstream trade journals I also contributed to as a freelance technology journalist, if I happened to trip over something worthy. But I knew those weren't the only reasons I would again find myself one of a mere handful of reporters (and one of the very few women) in a sea of talented engineers and scientists from all over the world.

IEDM drew only the most elite international scientists and engineers from a multitude of disciplines. The meet's Emerging Technologies sessions always had something worth note for me. Understanding what they were presenting was always a challenge as it is for any non-technical person like myself. What I'd developed over years of self-discipline was a capacity to hear them out and plow through all the literature until I understood it enough to write about it. Fortunately, I always had editors with engineering degrees behind their names to help make me look good in print. So there I was, off on assignment to another big city. The City, as we native Californians had always called San Francisco. And returning to my roots, which included the famed "Silicon Valley," made it special.

For the last few years some of the most noteworthy compound semiconductor technologists used the IEDM forum to roll out a truly new technology. Doing my homework on the plane, I noticed on the program that a man with a unique Japanese name, Shuji Nakamura, whom I'd heard a bit about already, would be presenting some new blue LED results using a compound semi material group called Group III Nitrides. As a specialist in the "oh gosh gee whiz.. What's REALLY new..." the Nitrides were right up my line. As one of what's collectively called the "wide bandgap" (WBG) semiconductors, along with silicon carbide (SiC) and zinc selenide (ZnSe), the Nitrides (aka: Gallium Nitride, or GaN) are uniquely tough stuff, meaning circuits designed in WBGs can withstand extreme heat and cold and function in very harsh conditions. That was their claim thus far, but those in the know knew they could also emit light in the blue spectrum. By the basic laws of nature, silicon can't do those sorts of things well. The Holy Grail for the blue spectrum was the illusive solid state blue laser, which companies like Philips in the Netherlands had been pioneering for some time... in ZeSe, with marginal results. There was only one commercial level blue LED player at the time, and that was a SiC company in Durham, North Carolina in the USA called Cree, which was was making decent progress in designing rather dim blue LEDs... but at least they worked! Unless Cree's devices got considerably brighter, SiC's best prospects remained in harsh temperature and power electronic applications.

I'd learned all that, and more, from the masters by attending countless esoteric technology meetings over the years prior to this meet. The place where I'd learned a tremendous amount was Washington DC in 1993 where the international WBG compound semi community gathered at a biennial meet called ICSCRM. As you'll see later in this story, that meet, which was the first time the compound semi community brought Russian scientists to the USA, was extremely pivotal and would provide tremendously important background to what I was about to witness and report on from San Francisco.

When I walked in especially early for the emerging technology session where Shuji Nakamura was to present, I sat in the back and kibitzed with IEDM's PR person (Gary ___), he being one of the few others among the thousand plus attendees who wasn't a technologist. He'd put me on to this session specifically when talking me into attending the meeting. That's what great PR people do. Gary had always been an ardent reader of my work for III-Vs Review and Military & Aerospace Electronics. He knew I was one of the few who'd actually attend and sit through the entirety of what he felt was IEDM's prize session, the emerging technologies. Gary was very excited about Shuji Nakamura and what was going on at Nichia. Gary noted to me that this was the first Japanese technologists he'd ever seen use his first name the way people do in the USA. From that day forward, Shuji was simply "Shuji." Once he came to the podium, I knew why.

Shuji Nakamura was the most effervescent technologist I'd ever seen take the stage... and I'd seen quite a few of them over the years headquartered in Silicon Valley. He wasn't shy. He wasn't "nerdy" looking. He was distinctive and his warmth simply shined through. He was obviously confident in what he was about to convey, and he was obviously proud of what he and his team were doing at Nichia. But there wasn't a thread of cockiness or smugness. He was simple, and genuinely... enthusiastic about it which told me that this was one of those type people who truly loved what he was doing. His English was difficult to cipher at first, but pretty soon my practiced ears picked out all the words. Then he did the classic "one picture is worth a thousand words" and pulled out a sample Blue LED, and shined it for the small audience to see.

It was the most beautiful blue light I had ever set my eyes on.

The brilliance of the device emitted the brilliance of Shuji's work, and spoke volumes all by itself. This was the first time Nichia's LED ever shed its light on the USA press. And because that press was me, it was obviously it was also the breakthrough the compound semi community had been waiting for. I broke the story in Electronic Engineering Times and wrote it in detail in III-Vs Review.

I've been championing the blue spectrum ever since. And this is their story.

[cattygurl]

Damn, bluejives. You're full of good tech/sci info.

Thanks! I've passed this on to other people!

[Dialectic]

This is freaking amazing. Admittedly I've only read the first two posts. God I love this stuff.

[bluejives]

http://www.time.com/time/asia/magazine/article/0,13673,501041004-702197,00.html