Band Gap Energy of Semiconductors

Theoretical Background / Context

• A semiconductor always possesses an energy gap between its valence and conduction bands.
• For the conduction of electricity, a certain amount of energy is to be given to the electron so that it can jump from the valence band to the conduction band.
• The energy needed is the measure of the energy gap (Eg) between the top and bottom of valence and conduction bands respectively.
• In case of insulators, the value of Eg varies from 3 to 7 eV. However, for semiconductors, it is quite small.

Principle of Work

• The semiconductor carrier board is assembled in the control panel.
• The control panel and the power supply are connected then the power supply is turned on and the current is adjusted on 5mA
• After that the heating coil is activated and the temperature versus the voltage are recorded once the carrier board reaches 150 degree celsius and starts to cool down.
• The voltage across the carrier board is measured with the multimeter and the temperature is measured through the control panel.