Основы физики и химии полупроводников - 55 стр.

UptoLike

ȼ ɭɪɚɜɧɟɧɢɟ ȼɭɥɶɮɚȻɪɷɝɝɚ ɩɪɢ ɷɬɨɦ ɩɨɞɫɬɚɜɥɹɟɬɫɹ
ɫɪɟɞɧɟɜɡɜɟɲɟɧɧɨɟ ɡɧɚɱɟɧɢɟ ɞɥɢɧɵ ɜɨɥɧɵ, ɪɚɫɫɱɢɬɵɜɚɟɦɨɟ ɩɨ ɮɨɪɦɭɥɟ:

21
3
1
3
2
DODOO
KK
. (5.5)
ɉɪɢ ɪɚɫɳɟɩɥɟɧɢɢ ɪɟɮɥɟɤɫɨɜ ɜ ɞɭɛɥɟɬ, ɜ ɫɥɭɱɚɟ ɛɨɥɶɲɢɯ ɭɝɥɨɜ
ɞɢɮɪɚɤɰɢɢ, ɦɟɠɩɥɨɫɤɨɫɬɧɵɟ ɪɚɫɫɬɨɹɧɢɹ ɦɨɠɧɨ ɨɩɪɟɞɟɥɹɬɶ ɩɨ
ɩɨɥɨɠɟɧɢɹɦ ɦɚɤɫɢɦɭɦɨɜ ɞɥɹ ɫɨɨɬɜɟɬɫɬɜɭɸɳɢɯ ɞɥɢɧ ɜɨɥɧ ɄĮ
1
ɢɄĮ
2
.
Ⱦɥɹ ɧɚɯɨɠɞɟɧɢɹ ɩɚɪɚɦɟɬɪɨɜ ɪɟɲɟɬɤɢ ɫɥɟɞɭɟɬ ɢɫɩɨɥɶɡɨɜɚɬɶ ɪɟɮɥɟɤɫɵ
ɫ ɛɨɥɶɲɢɦɢ ɡɧɚɱɟɧɢɹɦɢ ɭɝɥɨɜ, ɩɨɫɤɨɥɶɤɭ ɨɲɢɛɤɚ ɨɩɪɟɞɟɥɟɧɢɹ ɰɟɧɬɪɚ
ɬɹɠɟɫɬɢ ɪɟɮɥɟɤɫɚ ɭɦɟɧɶɲɚɟɬɫɹ ɫ ɪɨɫɬɨɦ ɭɝɥɚ ɨɬɪɚɠɟɧɢɹ.
5.2. Ɇɟɬɨɞɵ ɢɫɫɥɟɞɨɜɚɧɢɹ ɷɥɟɤɬɪɨɮɢɡɢɱɟɫɤɢɯ ɫɜɨɣɫɬɜ
5.2.1. ɍɞɟɥɶɧɚɹ ɷɥɟɤɬɪɨɩɪɨɜɨɞɧɨɫɬɶ
ɂɡɦɟɪɟɧɢɟ ɬɟɦɩɟɪɚɬɭɪɧɨɣ ɡɚɜɢɫɢɦɨɫɬɢ ɭɞɟɥɶɧɨɣ ɷɥɟɤɬɪɨɩɪɨɜɨɞɧɨɫɬɢ
ɩɨɡɜɨɥɹɟɬ ɭɫɬɚɧɨɜɢɬɶ ɬɟɪɦɢɱɟɫɤɭɸ ɲɢɪɢɧɭ ɡɚɩɪɟɳɟɧɧɨɣ ɡɨɧɵ
'
E
0
ɩɨɥɭɩɪɨɜɨɞɧɢɤɚ ɢ ɷɧɟɪɝɢɢ ɚɤɬɢɜɚɰɢɢ ɩɪɢɦɟɫɧɵɯ ɭɪɨɜɧɟɣ (ɫɦ. ɝɥ. 4). Ⱦɥɹ
ɪɚɫɱɟɬɚ ɷɬɢɯ ɜɟɥɢɱɢɧ ɩɨɥɶɡɭɸɬɫɹ ɮɨɪɦɭɥɚɦɢ (4.6) ɢ (4.8).
ɍɞɟɥɶɧɭɸ ɷɥɟɤɬɪɨɩɪɨɜɨɞɧɨɫɬɶ ɦɨɠɧɨ ɜɵɪɚɡɢɬɶ ɱɟɪɟɡ ɩɪɨɢɡɜɟɞɟɧɢɟ
ɷɥɟɦɟɧɬɚɪɧɨɝɨ ɡɚɪɹɞɚ ɧɨɫɢɬɟɥɟɣ ɬɨɤɚ (e = 1,6010
-19
Ʉɥɡɚɪɹɞ ɷɥɟɤɬɪɨɧɚ),
ɤɨɧɰɟɧɬɪɚɰɢɢ ɧɨɫɢɬɟɥɟɣ ɬɨɤɚ n, ɢ ɩɨɞɜɢɠɧɨɫɬɢ ɧɨɫɢɬɟɥɟɣ u:
V
= enu. (5.6)
ɇɚɢɛɨɥɟɟ ɩɪɨɫɬɵɦ ɫɩɨɫɨɛɨɦ ɢɡɦɟɪɟɧɢɹ ɭɞɟɥɶɧɨɣ ɷɥɟɤɬɪɨɩɪɨɜɨɞɧɨɫɬɢ
ɞɥɹ ɨɛɪɚɡɰɨɜ ɜ ɮɨɪɦɟ ɩɚɪɚɥɥɟɥɟɩɢɩɟɞɚ ɹɜɥɹɟɬɫɹ ɞɜɭɯɡɨɧɞɨɜɵɣ ɦɟɬɨɞ,
ɫɯɟɦɚ ɤɨɬɨɪɨɝɨ ɩɪɟɞɫɬɚɜɥɟɧɚ ɧɚ ɪɢɫ. 32.
ɇɚ ɷɬɨɦ ɪɢɫɭɧɤɟ ɩɨɤɚɡɚɧɚ ɤɨɦɩɟɧɫɚɰɢɨɧɧɚɹ ɫɯɟɦɚ ɢɡɦɟɪɟɧɢɹ
ɭɞɟɥɶɧɨɣ ɷɥɟɤɬɪɨɩɪɨɜɨɞɧɨɫɬɢ, ɩɪɢɧɰɢɩ ɞɟɣɫɬɜɢɹ ɤɨɬɨɪɨɣ ɡɚɤɥɸɱɚɟɬɫɹ ɜ
ɫɥɟɞɭɸɳɟɦ. ɉɪɢ ɩɪɨɯɨɠɞɟɧɢɢ ɬɨɤɚ I ɱɟɪɟɡ ɬɨɪɰɟɜɵɟ ɝɪɚɧɢ ɨɛɪɚɡɰɚ ɫ
ɧɚɧɟɫɟɧɧɵɦɢ ɧɚ ɧɢɯ ɨɦɢɱɟɫɤɢɦɢ ɤɨɧɬɚɤɬɚɦɢ (1,2) ɧɚ ɩɨɜɟɪɯɧɨɫɬɢ ɨɛɪɚɡɰɚ,
ɦɟɠɞɭ ɡɨɧɞɚɦɢ (3,4) ɜɨɡɧɢɤɚɟɬ ɪɚɡɧɨɫɬɶ ɩɨɬɟɧɰɢɚɥɨɜ U. ȼɟɥɢɱɢɧɚ
ɩɟɪɟɦɟɧɧɨɝɨ ɫɨɩɪɨɬɢɜɥɟɧɢɹ R ɩɨɞɛɢɪɚɟɬɫɹ ɬɚɤɢɦ ɨɛɪɚɡɨɦ, ɱɬɨ ɬɨɤ ɱɟɪɟɡ
ɝɚɥɶɜɚɧɨɦɟɬɪ ɫɬɚɧɨɜɢɬɫɹ ɪɚɜɧɵɦ ɧɭɥɸ.
ȼ ɷɬɨɦ ɫɥɭɱɚɟ ɧɚɯɨɞɢɦ: U = RI, ɞɚɥɟɟ ɭɞɟɥɶɧɚɹ ɷɥɟɤɬɪɨɩɪɨɜɨɞɧɨɫɬɶ
ɪɚɫɫɱɢɬɵɜɚɟɬɫɹ ɩɨ ɮɨɪɦɭɥɟ:
V
= LI/SU, (5.7)
ɝɞɟ Lɪɚɫɫɬɨɹɧɢɟ ɦɟɠɞɭ ɡɨɧɞɚɦɢ; Sɩɥɨɳɚɞɶ ɫɟɱɟɧɢɹ ɨɛɪɚɡɰɚ.
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