Laureation address – Emeritus Professor John W Allen

Emeritus Professor John W Allen
Honorary Degree of Doctor of Science

Laureation by Professor Malcolm Dunn
School of Physics and Astronomy
Friday 25 June 2010

Chancellor, it is my privilege to present Emeritus Professor John Allen for the Degree of Doctor of Science, honoris causa.

We read in the Book called Genesis, Chapter 1, verse 3 the following:

“And God said, Let there be light: and there was light.”

Man on the other hand has found this to be a much more challenging objective to fulfil.

From his first appearance on this planet, man has been engaged on the long and arduous journey of creating better and better sources of artificial light. Perhaps the discovery of fire proved an early stimulus, indicating the benefits of having something that enabled you to see after dark, and so man was inspired to enter upon a long progression of developments encompassing flames, oil-lamps, candles, gas-lights, and so on. Even at the start of last century sources were still of this primitive kind. Then Edison brought us the electric light, enabled through the perfection by him and Joseph Swan in the UK, of the incandescent lamp bulb. But the incandescent bulb was never going to be the end of the story, since, like fire before, most of its emission is as heat and not as light, an inefficiency that has become an ever increasing challenge to the attainment of an ever greener world.

Just as well then that a new way forward was demonstrated when in 1962 a scientific officer in the Services Electronic Research Laboratory at Baldock developed a novel type of lamp, which he referred to as a crystal lamp; a lamp that was efficient, compact and of long-life. The scientific officer was John Allen, our honorary graduand today. The lamp he created was the world’s first practical, visible light-emitting-diode (or LED as we now know it). Based on a minute crystal of gallium phosphide, less than half a millimetre across, the critical breakthroughs were discovering the appropriate dopants to add to the crystal, and how to connect it up to an electrical supply so that, when an electric current was passed through it, red light was emitted.

So successful was John in developing a practical lamp that like Edison before him he went “…into the practical production of it”, to quote Edison when referring to his own development of the incandescent lamp. Indeed the world’s first production line for the manufacture of the crystal lamp was immediately set up in 1962, with the lamps so produced finding their early applications in the display of digital information.

Surely this story is one for our own times. The need to take research breakthroughs into practical production for commercial and societal benefit must once again become an urgent imperative within our present culture. In this regard we would be well advised to learn from the example set by our honorary graduand, before it is too late.

In the intervening years the usage of LEDs has grown rapidly from specialist applications to the point where they are now set to dominate all lighting markets as they progressively replace both incandescent and fluorescent lamps.

John has also played an important role in the development of another pervasive electronic device. We all know about semi-conductors, after all they are essential components in our computers, televisions, iPods, and so on. Well there is another class of materials, first identified by John, and called by him semi-insulators; these being materials that are engineered to have a high electrical resistance. And where do you find these semi-insulators being used? Well the chances are you have a device in your pocket right now that uses them; the mobile phone. Semi-insulators are crucial in enabling these phones to operate at the high frequencies employed in wireless communications.

In 1968 through the generous financial support of Tullis Russell, the papermakers based in Fife, John Allen came to St Andrews as a Research Fellow. In 1972 he became the founding Director of the Wolfson Institute of Luminescence, in particular researching the material zinc selenide for making other types of his crystal lamps, and in 1980 was awarded a Personal Chair in Solid-State Physics.

With no time to tell you about his many other achievements along the way, I must now fast-forward to the present day. John Allen is still vigorously active in science, but now he is engaged in research on applications of crystal lamps. In conjunction with the horticultural industry he is exploring the effects of different wavelengths of light, generated by LEDs of course, on plant growth and the control of plant disease. In collaborations with medics he is investigating the use of LEDs as compact and portable light sources for activating the drugs used in photodynamic therapies as applied to the treatment of skin cancers. Two applications that can truly be said to relate to the healing properties of light.

Finally, I speak, I am sure, on behalf of all the undergraduates, postgraduates, research staff, academic staff, and support staff of this University that at one time or another have interacted with John. We would wish to honour you today not just for your prowess in scientific research and its application, but also for all those lucid and inspiring lectures, demonstrations and tutorials you have delivered to us over the years; for letting us see how you think about physics so that we can learn to do likewise; for sharing with us, particularly at times of our own perplexity, your clear insights into physics principles and concepts; for using your wide scientific knowledge to identify research paths to follow; for inspiring us to make a go of it; and finally for sustaining us in a continuing belief that scientific endeavour and its realisation into practical utility are always worthwhile, no matter what.

Chancellor, in recognition of his major contribution to scientific research and its application, I invite you to confer on Emeritus Professor John Allen the Degree of Doctor of Science, honoris causa.