582 



THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1956 



Finally for cases in which pi < 0.05, Table III can be used. Thus 



^(P2 , pi) = Qil/pi) - Q(20) + t(p2 , 0.05) (9.12) 



where 1/pi , and 20 are a values in Table III. 



X. THEORY OF RELAXATION 



In Section VIII attention was drawn to the fact that ion pairing in 

 semiconductors can be made to occur slowly enough so that its kinetics 

 can be followed. It is possible to characterize these kinetics by a relaxa- 

 tion time r, which we shall endeavor to calculate in the present section. 



4000 



2000 



1000 

 800 



600 

 500 

 400 



300 



In 

 o 

 d 



<5. 



100 

 80 



60 



50 



40 



30 



20 



10 







^ ^ 



0.050 



0.055 



0.060 



0.065 

 Pa 



0.070 



0.075 



0.080 



Fig. 16 — Plot, for small values of P2 of i(p2 , 0.05) from (9.9). 



