Energy Bands in an LED
Drag an LED to the LED socket. The energy bands that appear on both sides of the energy scale represent the bands and gap for materials associated with these LEDs.
Notice that the valence bands of both semiconductor materials are shaded darker than the conduction band. This shading indicates that the majority of electrons have energies associated with the valence bands. Electrons are naturally found in these bands because they seek the lowest possible energies. Also notice that energy of the energy gaps of both blocks are the same to represent that the LED is constructed of two blocks of the same semiconductor material.