With physical barriers limiting further increases in semiconductor electronic efficiency, scientists at the University of Pittsburgh redesigned the structure of the vacuum electronic device, allowing electrons to travel ballistically in a nanometer-scale channel without any collisions or scattering.
Pittsburgh — With the advent of semiconductor transistors—invented in 1947 as a replacement for bulky and inefficient vacuum tubes—has come the consistent demand for faster, more energy-efficient technologies. To fill this need, researchers at the University of Pittsburgh are proposing a new spin on an old method: a switch from the use of silicon electronics back to vacuums as a medium for electron transport—exhibiting a significant paradigm shift in electronics. Their findings were published online in Nature Nanotechnology July 1.
For the past 40 years, the number of transistors placed on integrated circuit boards in devices like computers and smartphones has doubled every two years, producing faster and more efficient machines. This doubling effect, commonly known as “Moore’s Law,” occurred by scientists’ ability to continually shrink the transistor size, thus producing computer chips with all-around better performance. However, as transistor sizes have approached lower nanometer scales, it’s become increasingly difficult and expensive to extend Moore’s Law further.
The ultimate limit of transistor speed is determined by the electron transit time, or the time it takes an electron to travel from one device to the other. Electrons traveling inside a semiconductor device frequently experience collisions or scattering in the solid-state medium.
The team extracted electrons from the silicon structure efficiently by applying a negligible amount of voltage and then placed them in the air, allowing them to travel ballistically in a nanometer-scale channel without any collisions or scattering.
Image: University of Pittsburgh News