Recent changes in high school curricula show a surge towards teaching modern physics. Thus, we should seek effective experiments on quantum physics phenomena. I believe that a tunnel diode can provide such an opportunity. The tunnel diode’s unique property of allowing a small “tunneling current” contrasts with the familiar behavior of resistors, light bulbs, and even ordinary diodes. I cannot be the only physics teacher who thinks it is amazing to perform experiments on quantum tunneling! In this article, I present the fundamentals of quantum tunneling (as I would to high school students), perform the familiar IV curve graph experiment, and go further to explain how the tunneling current can be made visible by adding a light-emitting diode.

1.
For example, this comes up in AP Physics 2 as “Wave Functions and Probability” and the Next Generation Science Standards require students to evaluate radiation as a “wave model or particle model.”
2.
See “
Barrier Penetration
,”
HyperPhysics
, http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/barr.html.
3.
Leo Esaki received the 1973 Nobel Prize for inventing the tunnel diode.
5.
A great video shows this experiment. See “#204: Basics of Tunnel Diodes and their applications, https://youtu.be/PuG8CCUbg58.
© 2021 American Association of Physics Teachers.
2021
American Association of Physics Teachers
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