Основы физики и химии полупроводников - 27 стр.

UptoLike

ВУЗ: 

ВГУ | Воронеж

Составители: 

Рубрика: 

2
2
2
k
m
E
=
. (2.7)
Ⱦɢɮɮɟɪɟɧɰɢɪɭɹ (2.7) ɩɨ k, ɩɨɥɭɱɢɦ
dk
dEm
k
2
=
. (2.8)
ɉɨɞɫɬɚɜɥɹɹ ɷɬɨ ɜ (2.5) ɢ (2.6), ɧɚɣɞɟɦ:
dk
dEm
kp
=
=
,
dk
dE
k
m
v
=
= 1
. (2.9)
ȼ ɬɚɤɨɦ ɜɢɞɟ ɜɵɪɚɠɟɧɢɹ ɞɥɹ ɢɦɩɭɥɶɫɚ ɢ ɫɤɨɪɨɫɬɢ ɩɨɫɬɭɩɚɬɟɥɶɧɨɝɨ
ɞɜɢɠɟɧɢɹ ɨɤɚɡɵɜɚɸɬɫɹ ɫɩɪɚɜɟɞɥɢɜɵɦɢ ɧɟ ɬɨɥɶɤɨ ɞɥɹ ɫɜɨɛɨɞɧɵɯ
ɷɥɟɤɬɪɨɧɨɜ, ɧɨ ɢ ɞɥɹ ɷɥɟɤɬɪɨɧɨɜ, ɞɜɢɠɭɳɢɯɫɹ ɜ ɩɟɪɢɨɞɢɱɟɫɤɨɦ ɩɨɥɟ
ɤɪɢɫɬɚɥɥɚ. ɂɦɩɭɥɶɫ ɪ ɜ ɷɬɨɦ ɫɥɭɱɚɟ ɧɚɡɵɜɚɸɬ ɤɜɚɡɢɢɦɩɭɥɶɫɨɦ ɷɥɟɤɬɪɨɧɚ.
ɋɨɡɞɚɞɢɦ ɜ ɤɪɢɫɬɚɥɥɟ ɜɧɟɲɧɟɟ ɩɨɥɟ ȿ. ɗɬɨ ɩɨɥɟ ɞɟɣɫɬɜɭɟɬ ɧɚ ɷɥɟɤ-
ɬɪɨɧ ɫ ɫɢɥɨɣ F = – qE, ɫɨɨɛɳɚɹ ɟɦɭ ɭɫɤɨɪɟɧɢɟ
dt
dk
dk
Ed
dk
dE
dt
d
dt
dv
a
2
2
11
==
.
Ɂɚ ɜɪɟɦɹ dt ɫɢɥɚ F ɩɪɨɢɡɜɨɞɢɬ ɪɚɛɨɬɭ
dt
dk
dEF
FvdtdA
=
.
ɗɬɚ ɪɚɛɨɬɚ ɢɞɟɬ ɧɚ ɩɪɢɪɚɳɟɧɢɟ ɷɧɟɪɝɢɢ ɷɥɟɤɬɪɨɧɚ dE:
dt
dk
dEF
dE
=
.
Ɉɬɫɸɞɚ ɧɚɯɨɞɢɦ
=
F
dt
dk
.
ɉɨɞɫɬɚɜɥɹɹ ɷɬɨ ɜ ɩɪɚɜɭɸ ɱɚɫɬɶ ɜɵɪɚɠɟɧɢɹ ɞɥɹ ɚ, ɩɨɥɭɱɢɦ
2
2
2
dk
EdF
a
=
. (2.10)
Ɏɨɪɦɭɥɚ (2.10) ɭɫɬɚɧɚɜɥɢɜɚɟɬ ɫɜɹɡɶ ɦɟɠɞɭ ɭɫɤɨɪɟɧɢɟɦ ɷɥɟɤɬɪɨɧɚ ɚ ɢ
ɜɧɟɲɧɟɣ ɫɢɥɨɣ F, ɞɟɣɫɬɜɭɸɳɟɣ ɧɚ ɧɟɝɨ ɫɨ ɫɬɨɪɨɧɵ ɜɧɟɲɧɟɝɨ ɩɨɥɹ ȿ. Ɉɧɚ
ɜɵɪɚɠɚɟɬ, ɫɥɟɞɨɜɚɬɟɥɶɧɨ, ɜɬɨɪɨɣ ɡɚɤɨɧ ɇɶɸɬɨɧɚ. ɂɡ ɷɬɨɣ ɮɨɪɦɭɥɵ ɫɥɟɞɭɟɬ,
ɱɬɨ ɩɨɞ ɞɟɣɫɬɜɢɟɦ ɜɧɟɲɧɟɣ ɫɢɥɵ ɷɥɟɤɬɪɨɧ ɜ ɩɟɪɢɨɞɢɱɟɫɤɨɦ ɩɨɥɟ ɤɪɢɫɬɚɥɥɚ
ɞɜɢɠɟɬɫɹ ɜ ɫɪɟɞɧɟɦ ɬɚɤ, ɤɚɤ ɞɜɢɝɚɥɫɹ ɛɵ ɩɨɞ ɞɟɣɫɬɜɢɟɦ ɷɬɨɣ ɫɢɥɵ
ɫɜɨɛɨɞɧɵɣ ɷɥɟɤɬɪɨɧ, ɟɫɥɢ ɛɵ ɨɧ ɨɛɥɚɞɚɥ ɦɚɫɫɨɣ
22
2
/ dkEd
m
ɷɮ
=
. (2.11)
Ɇɚɫɫɚ m
ɷɮ
ɧɚɡɵɜɚɟɬɫɹ ɷɮɮɟɤɬɢɜɧɨɣ ɦɚɫɫɨɣ ɷɥɟɤɬɪɨɧɚ. ɉɪɢɩɢɫɵɜɚɹ
ɷɥɟɤɬɪɨɧɭ, ɧɚɯɨɞɹɳɟɦɭɫɹ ɜ ɩɟɪɢɨɞɢɱɟɫɤɨɦ ɩɨɥɟ ɤɪɢɫɬɚɥɥɚ, ɦɚɫɫɭ ɬ
ɷɮ
, ɦɵ
27

Страницы