
42 PHYSICAL FOUNDATIONS OF MICROWAVE TECHNOLOGY
same on both sides of the junction, a difference in the potential energy on the two
sides results in an
electrical potential barrier
(EB) energy. The potential barrier forms
a blockade, an electrical brick wall, to electrons trying to pass over the junction.
Unless an electron has sufficient energy, it cannot leap over the potential barrier.
Now consider the Esaki tunnel diode. The transition region between P-type
and N-type semiconductor material in a tunnel diode is on the order of 100
angstroms, rather than the 10,000 angstroms that is typical in ordinary
PN
junction
diodes. ...