QUE : WHAT ARE N-TYPE AND P-TYPE SEMICONDUCTOR ?

SOL; Types Of Extrinsic Semiconductor     (i) N Type Semiconductor    (ii) P Type Semiconductor

(i) N Type Semiconductor                                                                                                                         Group 14 elements are tetravalent. when some group 15 elements (which are pentavalent) are added to the group 14 elements there atoms linked group 14 elements by four covalent bonds and have an extra electron which is not involved in any bonding. the movement of free electron induces the conductivity in the crystal. since conductivity is due to the electrons so it is called n type semiconductor. Example Ga-P, Si-Al etc.

(ii) P Type Semiconductor                                                                                                                          Group 14 elements are also doped by adding elements of group 13 which are trivalent in nature. Group 13 elements link to group 14 elements three covalent bonds. Group 13 elements unable to provide electron to 4th Bond of group 14 elements leads to the formation of holes in the crystal. The movement of holes induces the conductivity in the crystal. Since the conductivity is due to the holes so it is called P type semiconductor. Example Si-Al, Ge-Ga etc.