What is Quantum Tunneling?

Quantum tunneling is the basis of Phiar’s technology. At the heart of the phenomenon is the quantum mechanical notion that electrons are "waves" rather than "particles."

As shown in Figure 1, the classical electron is a particle and it cannot pass through an insulator’s barrier; unless it has a high enough energy to cross above the barrier, it simply bounces off.  

Because quantum mechanics tells us we can only predict the probability of an electron’s location, traditional Newtonian physics no longer applies.

Indeed, a more accurate representation of an electron is a probability distribution, as seen in the bottom two diagrams in Figure 1. When an electron’s location nears the edge of the barrier, there is a small likelihood that the electron could appear on the other side of the barrier, which is represented by the green line. As one would expect, a thinner barrier leads to a greater probability that the electron will appear on the other side.

When an electron “appears” in a new place after traveling through an insulator, it is said to have “tunneled” through the insulator.

This phenomenon is the basis for the MIM diode, which we explore next.