It is over forty years since quantum mechanical tunnelling of electrons through thin semiconductor barrier layers, and resonant tunnelling through double barrier diodes, were first demonstrated. While the physics associated with quantum confinement in semiconductor multilayers has been exploited in transistor and laser devices, devices based on tunnelling are not a commercial success. One principle barrier has been the ability to manufacture sufficiently devices with sufficient uniformity with a wafer and reproducibility between wafers to permit low cost production. I discuss projects over the last 25 years to achieve a manufacturable process and show the interesting science encountered on the way, leading to the receipt of a first commercial order for tunnel detector diodes this year.
Professor Michael Kelly is the Emeritus Prince Philip Professor of Technology in the University of Cambridge since 2016, having been the inaugural holder of the chair since 2002. He has also been a regular visitor to the MacDiarmid Institute, Victoria University of Wellington since 2012, serving on its international advisory board since its inception.
Education: Maths and Physics to MSc level at Victoria University of Wellington in New Zealand 1971; PhD at Cambridge in 1974 in solid state theory.
Career: Post-doctoral research until 1981.
GEC Hirst Research Centre 1981-92: developed two new families of microwave devices that went, and are still, in production with E2V Technologies at Lincoln.
University of Surrey 1992-2002 including a term as Head of the School of Electronics and Physical Sciences.
Non-executive Director of Surrey Satellite Technology Limited 1996-2002. Executive Director of the Cambridge-MIT Institute, 2003-5. Chief Scientific Adviser to the Department for Communities and Local Government 2006-9. Non-Executive Director of the Laird plc 2006-15.
Fellow of the Royal Society of London, the Royal Academy of Engineering and Honorary Fellow of the Royal Society of New Zealand. Member of the Academia Europaea. Fellow (and former Vice-President) of the Institute of Physics and Fellow of the Institution of Engineering and Technology. Senior member of the IEEE and member of the American Physical Society.