Both the values and the intrinsic conductivity expression

●  383 

termed ptype because positively charged particles are primarily responsible for electrical conduction. Of course, holes are the majority carriers, and electrons are present in minority concentrations. This gives rise to a predominance of the second term on the righthand side of Equation 12.13, or
� � p�e��h  (12.17) 



12.12 THE TEMPERATURE VARIATION OF CONDUCTIVITY AND CARRIER CONCENTRATION
384  ●  Chapter 12 / Electrical Properties 




10,000  –100  0  
1,000 

Intrinsic  electrical conductivity  




[Adapted from G. L.  
Intrinsic  Bardeen, Phys. Rev.,  
0.1

100  200  400  600  1000 

ln � � C �Eg 2kT  (12.18) 

where C represents a temperatureindependent constant and Eg and k are the band gap energy and Boltzmann’s constant, respectively. Since the increase of n and p with rising temperature is so much greater than the decrease in �e and �h, the dependence of carrier concentration on temperature for intrinsic behavior is virtually the same as for the conductivity, or
ln n � ln p � C� �Eg 2kT  (12.19) 
