Figure 41-17 Cross section of an LED (the
device has rotational symmetry about the
central axis).The p-type material, which is
thin enough to transmit light, is in the form
of a circular disk.A connection is made to
the p-type material through a circular metal
ring that touches the disk at its periphery.
The depletion zone between the n-type material
and the p-type material is not shown.