Draw the energy band diagrams of (i) n-type and (ii) p-type semiconductor at temperature, T 0K In - Physics - Semiconductor Electronics Materials Devices And Simple Circuits

Question

Draw the energy band diagrams of (i) n-type and (ii) p-type
semiconductor at temperature, T > 0K In the case n-type Si
semiconductor, the donor energy level is slightly below the bottom
of conduction band whereas in p-type semiconductor, the acceptor
energy level is slightly above the top of the valence band Explain,
what role do these energy levels play in conduction and valence
bands

Sanjay Singh · Accepted Answer

Dear student

At a temperature of 0 kelvin conduction band of a semiconductor is completely empty and it behaves as an insulator In case of n type semicnductor as each doner atom donate one electron as it complete its octet just by using its four electrons so it shows very less affinity for the fifth electronand fifth electron is almost free from the nuclear attraction and all these free electrons can easily go to the conduction band just by gaining little of energy So theseelectrons form a new level of energy called doner impurity energy level that lie just below the conduction band In case of p type semicnductor as each acceptor is responsible for one hole that is absense ofelectron in the covalent bond now movement of holes ofcourse inhance theirconductivity but it requires breaking of covalent bond so this fact makes them require more energy than the fifth free electron would need in case of n type semicnductor to participate in conduction So they form a new energy band that just lie above the valence bandand is called acceptor energy level