Na-8 Band Gap Energy

Aim

To demonstrate the bang gap energy of a pn junction.

Apparatus

  • Blue LED
  • Red LED
  • Galvanometer
  • Desk Lamp
  • U.V. source

Band Gap

Band Gap Energy Setup.

Description

A red LED is illuminated with a desk lamp. The photons have enough energy for the electrons to overcome the energy gap in the pn junction and a current is displayed on the galvanometer. If the same desk lamp illuminates a blue LED the photons do not have enough energy to produce a current flow. However if the leds are illuminated with a UV source a current will now flow.