Extrinsic Material:

THE CHARACTERISTICS OF SEMI CONDUCTOR material can be alter significant bin addition of certain impurity atoms into the relatively pure se conductor material called doping process is called an extrinsic material.

n-type material    ; the n type material is created  by introduction those impurity element that have five valence electrons such as antimony , arsenic and phosphorous . These diffused impurities with five valence electronics are called donor altos. Note that after doping the n type material is still electrical neutral. Since number of protons in a nuclear is still equal to number of free and orbiting negatively charged electrons in the structure.