

G8G 



THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1956 



(K/^eP) 



1/2 



l.o X 10" cm. 



(1) 



where A' is tlie dielectric constant, c is the electronic charge, and )3 is the 

 constant 



^ = e/kT = n„/D,, = fxp/Di 



(2) 



which at room temperature is 38.7 \'olt~\ We shall denote points in the 

 P and A'' contacts on the edges of the space charge regions by oo and 

 WW respectively. Thus Uoo is the electron density in the P^ contact at the 

 junction, and Ho is the electron density at the same junction in the 

 middle region. Similarly p„.,„ is the hole density at the junction in the 

 A^ contact and pu, is the hole density at the junction in the middle region. 

 We shall denote equilibrium carrier densities in the three regions by 

 np+ , 7ip , Pp , Pn+ . Typical values for the parameters characterizing 



N" 



(a) 



w 



X- 



> 



-V, 



oo/ 1 



WW 



V= 



1=0 



(b) 



(Cj 



w 



V\^. 1 — SchcuKitic represent al ion ol' (lie IMX (li(Ki(! with tli(> 1'+ and N+ con- 

 tacts regarded as extending to infinity. (1)) .shows the; tdect rostatic potential in 

 equilibrium and (c) show.s the potential when a forward current Hows. 



