DC FIELD IN A "SWEPT INTRINSIC SEMICONDUCTOR 



667 



T : temperature, °K. 



ip : electric potential, volts. 



ip : hole current density, amps/m^. 



in : electron current density, amps/m^. 



lip', hole mobility constant, m^ /volt-sec. 



Mni electron mobility constant, m^/volt-sec. 



g : rate of generation of hole-electron pairs, m~^ sec""\ 



r : rate of recombination of hole-electron pairs, m"'^ sec~\ 

 An order-of-magnitude comparison of the terms in (2) or (3) reveals 

 that the currents probably have Uttle influence on the field distribution. 

 For example for 



5 amps/m^, 



amp-m' 

 10~m. 



finkT = 1.44 X 10"'' ' 



N = 2X 10'' m~', and L 



/ -^dy^ S'WL ^ 3-10" m 



Jo 



IJinkT 



while 



L 



dn 



T- dy 



dy 



n(0) - n(L) ^N = 2.10''m- 



On this basis, the current terms in (2) and (3) can be omitted without 

 serious error. No use then has to be made of (5) and (6), so the govern- 

 ing equations for the intrinsic region become: 



dE q , 

 dy K 



n), 



(10 



1 



Fig. 2 — Qualitative picture of potential distribution in reverse-biased n-m- 

 trinsic-p structure. 



