692 THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1956 



Upon invoking the second equation of (22) we get 



fiVp = i" "^ f ^^ /n — (26) 



In — Olp Ho 



and 



n^=^no+ ^" ~ ^^^ w;. (27) 



We see that Vp is always positive in sign whatever the sign of /„ — hip . 

 We now define a parameter 



(28) 



(29) 



(30) 



Combining (23), (27) and (30) gives the equation for 7 as a function of 

 total current 



7=1- 



In — bip W 



2Dn Un 



_ n (7/7 j^ - 1 ^^^^ 



y /o VI + &(7/7»)^ 

 where 



7co' = &/i2 (32) 



and /o is a unit of (particle) current density characteristic of the device 



Z. = i^^ = 4 m ^ (33) 



A typical value for e /o in a silicon diode is 



e /o '-^ 200 amp/cm" (3-1'^ 



based on (3). 



i 



