Band Gaps

Conductors, insulators and in between

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• The band gap separates bound (valence) and free (conduction) electrons.
• Metals: no gap. Silicon: 1.1 eV. Insulators: large gaps.
• Semiconductors conduct better when hot. Holes act as positive carriers.

Steps

1. Energy bands
2. Heat it up
3. A big jump
4. Silicon’s threshold
5. The colour of an LED
6. Holes