Some of the biggest problems in applied science – such as personalized genome mapping and affordable renewable energy – require the aid of some of the world’s smallest devices. In the meticulously maintained clean room at CSU Northridge, students create and test these nanotech devices under the direction of Assistant Professor Henk Postma.
Going from Theory to Reality
Imagine an atom thick layer of honeycomb-structured carbon, called graphene. Now cut a slit the width and length of a few atoms into that tiny sheet. Finally, draw a strand of human DNA through it so that the structure unwinds, enabling it to be more easily “read.” Postma and his students are working on devices to accomplish this task, with the possibility of dramatically reducing the time and cost involved in sequencing the human genome. If made widely available, a future nanodevice could allow each of us to identify potential genetic diseases and other risk factors prior to the onset of illness.
Seeing Really, Really Small Objects
Working in the field of nanotechnology presents a challenge: How do you observe something that is 1000 times smaller than the width of a human hair? A light microscope is useless at this scale. Even a scanning electron microscope (top left) cannot achieve the necessary resolution, though it is a useful tool in preparing materials. CSUN scientists have other tools available, including an atomic force microscope (top right) that transmits information on the shape of atoms in much the same way as a record needle transmits recorded sound. Using the atomic force microscope, an atom thick web of carbon nanotubes (bottom left) becomes visible. Sometimes you can measure the effect of a device rather than making a direct observation. For the DNA device, the CSUN lab uses a specialized tool to measure changes in ion and electron resistance (bottom right).
In the world of the very small, a single dust particle is a giant capable of destroying a device. The CSUN clean room (top left) provides a safe place in which experiments take place. Pressure gauges (top right) show the precision with which the environment in the clean room is maintained. The white suits (bottom left and right) limit the contamination from dust, lint and microorganisms carried around by humans. One tool utilized in the clean room is a spherical evaporator (top left) capable of depositing an atom thick layer of super-heated metal on a test surface.
Among a kaleidoscope of color representing hundreds of previous devices and test surfaces, Postma shows a student-designed prototype solar power cell. The cell generates energy via the weak photosensitivity of lab generated carbon nanotubes.
His students explored the nanoscale solar solution not for miniaturization, but as an economical option for large surfaces like rooftops. Today’s solar technology is designed for peak efficiency and minimal use of space – at a significant cost. However, if you can coat a large surface area with millions or billions of what may one-day be cheap carbon structures, then renewable energy becomes accessible to a much larger group of consumers.