wat is donor level nd acceptor level..??

In a pure semiconductor the difference between the conduction band and the valance band is more than the energy gap in a doped semiconductor. Now, when the semiconductor is doped the doped atoms increases the conductivity of the semiconductor. Thus, in n-type semiconductor, electrons from the doped element are close to the conduction band. This new energy level below the conduction band is called donor level, because an electron there is easily donated to the conduction band.

In simple words, donor level is the energy level due to free electrons from the n-type doped atoms.

Similarly, in an p-type semiconductor, extra holes are found due to doping. These holes create extra energy levels just above the valence band. In this condition it takes relatively lesser energy to move another electron into a hole. This level is called acceptor level.

In simple words, acceptor level is the energy level due to holes from the p-type doped atoms.