David J Lockwood
Principal Research Officer
National Research Council
- BSc, MSc, PhD and DSc, University of Canterbury
- DSc University of Edinburgh
David's research work is centered on the optical properties of low dimensional materials at the nanoscale and recently has focused on Group IV and III-V semiconductor quantum dots and transition-metal magnetic nanowires and nanorings. The research is aimed at providing new technologies for improving the performance of devices involved in information communications (e.g., the internet) and information storage (rewritable digital memories), and developing quantum computers.
Advice to Students:
I'd suggest taking general science or engineering courses at university to find out what area of nanotechnology appeals to them the most and then proceed to higher-degree training in that area.
Q: When did you first find that your career path focused on nanotechnology?
Lockwood: Perhaps somewhat surprisingly I started research in the nanotechnology area in 1964, long before the ‘nano’ buzz word took off. I was studying for my Master’s thesis the diffraction of laser light (obtained from a homemade HeNe laser, which was a brand new research ‘tool’ in those days) from asymmetric colloids dispersed in water that could be aligned under the action of an intense sound field. Some of the colloids, for example, were needle-shaped and had diameters of less than 100 nm.
Q: What current nanotechnology applications are you working on?
Lockwood: I am systematically investigating the light emitting properties of silicon-germanium alloy and germanium quantum dots and quantum wires for applications in silicon photonics based on existing silicon CMOS technology. The characteristics of the luminescence obtained from these nanostructures can be readily altered through strain or band gap engineering, for example, by appropriately modifying their growth conditions. The overall aim is to produce an efficient light source from these materials that could be readily integrated into existing electronic integrated circuit fabrication processes (see below for more details).
Q: What's the most rewarding thing about working with nanotechnology?
Lockwood: From an experimental point of view, it is most fascinating and rewarding to see how we can characterize the physical properties of such tiny structures that are essentially invisible to the unaided eye. There are some techniques like transmission electron microscopy that can show you what they look like at almost atomic scale, but most optical techniques for example are essentially macroscopic. And yet we have been able to observe light emission at room temperature from a crystalline-Si single quantum well just 1 nm (two unit cells) thick! Our modern analysis tools are so sensitive.
Q: Is there an example you can provide that shows how something you’ve worked on has positively impacted the world?
Lockwood: Full implementation of silicon photonics in today’s electronics industry requires ideally a silicon-based laser light source. Such sources are not yet available, primarily because silicon (or germanium) has an indirect band gap. We have invented devices based on nanometer thick quantum wells of silicon spaced by silicon dioxide that emit bright red light at room temperature. Researchers in Japan at Hitachi Ltd. have now taken up this idea and produced, in a heroic engineering project, stimulated emission from such a structure. With further engineering development the long awaited silicon laser could now be possible. Such a laser will allow the development of fully silicon-based optical (or photonic) integrated circuits where information is carried not by electrons but by light (or photons). This circuitry is needed because the speed at which information can be transmitted in electronic integrated circuits has reached a limit governed by electrical resistance in the connecting wires. The use of photonics overcomes this barrier – information will now travel in our devices as fast as it ever will, at the speed of light! The ultimate goal is to replace electronic computation with the photonic equivalent.
Q: What do you think is the single greatest impact nanotechnology has had on the world thus far?
Lockwood: The development of modern electronics has had an enormous impact on every aspect of our daily lives. We utterly depend on computers of all types, cell phones, personal assistant devices in our pockets or purses and in automobiles, and the internet for communicating information of all types. None of this would have been possible without the development of the integrated circuit and associated engineering developments through nanotechnology.
Q: Please give an example of what you envision nanotechnology applications leading to in the future.
Lockwood: I think applications in biology will dominate this century. Using nanotechnology at the biomolecular level, cures will be found for cancers, human organs and body parts will be produced by artificial means, and much needed biofuels will be produced. On the physical side, applications of nanotechnology in energy production and storage will abound through solid oxide fuel cell, battery, and electrochemical capacitor development. Such advances will enable a more practical and efficient use of electricity by producing clean in-situ energy at a wide range of power requirements, for powering our vehicles, and for storing surplus energy production from alternative sources such as solar and wind power, respectively.
Q: Do you find yourself working more in a team situation, or more alone?
Lockwood: I have always worked in small teams, usually ranging in size from two to five people. In recent years I find I am increasingly working with larger and larger teams. The problems we tackle are so complicated nowadays that you need lots of specialists working together to make any progress. This mix of people frequently transcends the traditional silos of physics, chemistry, biology, and engineering.
Q: If you work more as a team, what are some of the other areas of expertise of your team members?
Lockwood: The areas of expertise include crystal growth using numerous methods, but especially epitaxial growth methods; nanofabrication procedures; scanning electron microscopy; transmission electron microscopy; atomic force microcopy; focused ion beam; infrared, Raman, emission and absorption optical spectroscopies; electron spin resonance; nuclear magnetic resonance; Auger spectroscopy; secondary ion mass spectroscopy; x-ray diffraction and reflection; neutron scattering; organic and inorganic chemistry; and biochemistry.
Q: Did your university training help you in your nanotechnology work?
Lockwood: The university training I received as a physicist was quite general and I have found that it has enabled me to develop the skills and learning necessary to carry out a wide variety of experimental and theoretical tasks in areas of nanotechnology related to the properties of condensed matter systems and their applications. My doctoral thesis work solidified my expertise in investigating the optical properties of nanosystems.
Q: Do you have a mentor? Did you in your college years?
Lockwood: I have no mentor, but I now mentor others. I had no mentor at Canterbury University, but my PhD supervisor, Professor Alister McLellan, was amazingly supportive and gave me essentially a free hand to develop my own research program in laser Raman spectroscopy, which included co-supervising the work of another PhD student.
Q: If you had to do it all over again, would you still focus on nanotechnology applications?
Lockwood: I work for the Government of Canada, and thus serve the Canadian public. I could not be sure I would take the same path if I was to do it all over again. We do whatever the needs of Canadians require at the time and there are many choices that are made along the way. For example, I could have been contributing in large-scale energy issues rather than nanotechnology areas.
Q: If a high school or college student was interested in nanotechnology, what advice would you give them to help prepare take on those roles?
Lockwood: I would suggest first taking general science or engineering courses at university to find out what area of nanotechnology appeals to them the most and then proceed to higher-degree training in that area. You should enjoy your training. Finding a good supervisor and/or mentor is essential; ask around.