3.5. .
: , , .
, , . , :
n0, p0 .
, , , , G R .
, τn, τp.
, , ∆n=∆p, . , , , , τn, ∆n/ τ, ∆n .
(3.29)
(3.30)
:
(3.31)
∆n0 .
(3.31) , τn τp =2,73 .
, , L, . , L τ:
(3.32)
Dn Dp ,
Dn=kTun/q, Dp=kTup/q.
ξg ξ.
, .
R0 n0 p0 G:
(3.33)
(3.34)
. , ∆n, ∆p<<(n0+p0) :
(3.35)
|
|
.
, ∆n=∆p>>(n0+p0) :
(3.36)
. :
(3.37)
:
(3.38)
, (). , .
. , , [I].
, , . : .
,
:
(3.39)
Dp, Dn , 2 /
, . , , , .
, :
(3.40)
(3.41)
(3.40) (3.41) : , , .
(3.40) (3.41) :
(3.42)
(3.43)
8. .
∆n. ∆n. ∆n t .
1020 3, 7,1 ·10 23 1 .
: ; ∆n 2 .
, , ?
:
t=0 ( ) ∆n:
.
,
|
|
C1=ln(∆n) t=0,
.
. t t=0, :
:
2
, .
, , :
Ln .
3.6. 3
3.6.1. . , , x1=2 ∆p=1014-3, x2=4,3 ∆p=1013-3.
3.6.2. τ - , t1=10-4c 10 , t2=10-3c.
3.6.3. (300 ), Un=38002/(·).
3.6.4. , T1=300 K ρ1=0,4·, T=500K-ρ2=0,001·. .
3.6.5. p Na=1023-3, ξ=0,05. T1=77K T2=300K, Up=0,01 2/(·) .
3.6.6.
2·10 5 2 1. , Π=1028-3?
3.6.7. p =300 ρ=6·10-4·, Na=5,6·1026-3, Lp=3·10-4. .
3.6.8. 10 16 3 , . , 1 · 2 , . 1400 2 / (·).
3.6.9. n . 1020 3. , : ρ=2·10-2·, τ=10-4, Un=0,362/(·) Up=0,172/(·) ni=1,3·1019-3.
, .
3.6.10. 6,22 /(·) 290 . , τ=3·10-8.
4.
. - , .
. , , , ..
|
|
[I].
: - , - (), . , , . .
4.1. -.
. - p - n . - .
- , p , n . p - n , 4.1..
|
a) )
|
)
. 4.1. () p - n () , ().
, , .
p - n , . 4.1.. n p , n ,
, Na. , , . , -n : ; () , . 4.1, *n=ni2 .
- n- -n , ( ) Δφ0. . -n
Δφ0 = φ ln (p * n /ni2) = φ ln (Na* N / ni2) (4.1)
ni - ;
φ = kT / q .
(. 4.1) Δφ0. Δφ0 >> φ, n , n = N . << = Na.
|
|
, , , . -n U . , Δφ0 + U, Δφ0 U. , n-, - -n ; - n- . -n , . , -n . - n .
(4.2)
N(x) = - Na < 0 N() = N x > 0
, φ(x) , . - (-lp) (. 4/1), ,n << Na, ≈ Na. (-lp) , E (-lp) = 0. , n- ln - , ,n << N, n ≈ N, E (ln) = 0.
, φ (-lp) = 0. , Δφ0, φ(ln) = Δφ0.
- n-, :
φ1() = Δφ0 (qN0 / 2 εε0)* (x + lp)2 (4.3)
φ2() = (qN / 2 εε0)* (x + ln)2 (4.4)
:
E1(x) = dφ1/ dx = - (qNa / εε0 ) * (x + lp) (4.5)
E2(x) = dφ2/ dx = (qN / εε0 ) * (x - ln) (4.6)
E1(0) = E2(0) ,
Q = SqNalp = SqN ln, (4.7)
N / Na = lp / ln. (4.8)
(4.8) , , .
φ1(0) = φ2(0) .
L0 = lpln=[2 εε0 Δφ0 1/q(1/Na+1/N)]½, (4.9)
, ε0 - ;
ε .
, , ,
Δφ = Δφ0 U; (4.10)
"-" , "+" .
. (4.10) (4.9) :
l = l0 (1 U / Δφ0)1/2 (4.11)
(4.1) (4.10) n- - .
Δn = pn pn0 (exp (U / φT) 1), (4.12)
Δnp = np np0 (exp (U / φT) 1), (4.13)
, . . , .. . .
|
|
. -n . S :
(4.14)
.
-n ,
(Δn / nno << 1), : Δnp = Δn(0) exp (x / Ln)
Δ0 = Δ(0) exp (x / L) n. Δn(0) Δ(0) (4.12) (4.13), :
Δnp() = npo[exp ( U / φT) 1]exp (x / Ln), (4.17)
Δpn() = pno[exp ( U / φT) 1]exp (- x / Lp), (4.18)
( = 0), S , :
(4.19)
:
I0 = qS (Dp / Lp) * pno + (Dn / Ln) * npo (4.20)
.