In semicondutors the usually doped impurities are penta&trivalent by this conductivity increases,,,,,,so my question is what happens if we add six valent or two valent then what happens to conductivity of the semiconductor????????????pls explain

dear aditya kulkarni,

The ease with which electrons in a semiconductor can be excited from the valence band to the conduction band depends on the band gap between the bands. The size of this energy bandgap serves as an arbitrary dividing line (roughly 4 eV) between semiconductors .

and this enrgy is not provided in case if we add six valent  or two valent.

BEST OF LUCK

We are all IITians and here to help you in your IIT JEE preparation.
Now you can win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.
Now you score 5+15 POINTS by uploading your Pic and Downloading the Askiitians Toolbar : Click here to download the toolbar..  
AMAN BANSAL