When an electron quantum tunnels, it does not physically move through a barrier in the classical sense, nor does it "teleport" in the way it is commonly understood. Quantum tunneling is a phenomenon that occurs at the quantum level, governed by the principles of quantum mechanics.
In quantum mechanics, particles like electrons are described by wavefunctions, which are mathematical descriptions that assign probabilities to different outcomes. When an electron encounters a potential barrier, according to classical physics, it would not have enough energy to overcome the barrier and pass through it. However, in quantum mechanics, there is a finite probability that the electron's wavefunction can extend into the classically forbidden region, allowing it to "tunnel" through the barrier.
During the tunneling process, the electron's wavefunction extends into the barrier region, and there is a non-zero probability of finding the electron on the other side. However, it is important to note that the electron's position is not precisely determined during tunneling. Instead, it exists in a superposition of states, where it has a probability of being on one side or the other.
Quantum tunneling is a purely quantum phenomenon that arises due to the wave-particle duality of matter. It is not accurately described by classical concepts of particle motion or teleportation. Instead, it involves the probabilistic nature of quantum systems and the wave-like behavior of particles at the quantum level.