MIM diodes consist of a “sandwich” of two metals, with two insulators in between. This allows an electron not so much to move through materials as to tunnel through insulators and appear almost instantaneously on the other side.
Now, researchers have found that the addition of a second insulator can enable “step tunneling,” a situation in which an electron may tunnel through only one of the insulators instead of both. This in turn allows precise control of diode asymmetry, non-linearity, and rectification at lower voltages.
“This approach enables us to enhance device operation by creating an additional asymmetry in the tunnel barrier,” says the university's Professor John Conley, "it gives us another way to engineer quantum mechanical tunneling and moves us closer to the real applications that should be possible with this technology.”
Three years ago the university announced the creation of the first successful, high-performance MIM diode and it remains the world leader in the technology.
More sophisticated microelectronic products could be possible with the MIIM diodes, say the researchers, not only improved liquid crystal displays, cell phones and TVs, but such things as extremely high-speed computers that don’t depend on transistors, or “energy harvesting” of infrared solar energy, a way to produce energy from the Earth as it cools during the night.
MIIM diodes faster devices than silicon-based chips and could be produced on a huge scale at low cost, from inexpensive and environmentally benign materials, says the university.
Image: MIIM diode, Oregon State University