Основы физики и химии полупроводников - 52 стр.

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ɦɧɨɝɨɤɚɧɚɥɶɧɵɣ ɚɦɩɥɢɬɭɞɧɵɣ ɚɧɚɥɢɡɚɬɨɪ, ɤɨɬɨɪɵɣ ɪɚɡɞɟɥɹɟɬ ɫɢɝɧɚɥɵ,
ɜɨɡɧɢɤɚɸɳɢɟ ɨɬ ɤɜɚɧɬɨɜ ɫ ɪɚɡɧɨɣ ɷɧɟɪɝɢɟɣ (~150 ɷȼ). Ɋɚɡɪɟɲɟɧɢɟ ɜɩɨɥɧɟ
ɞɨɫɬɚɬɨɱɧɨ ɞɥɹ ɭɜɟɪɟɧɧɨɝɨ ɪɚɡɞɟɥɟɧɢɹ ɯɚɪɚɤɬɟɪɢɫɬɢɱɟɫɤɨɝɨ ɢɡɥɭɱɟɧɢɹ ɨɬ
ɫɨɫɟɞɧɢɯ ɷɥɟɦɟɧɬɨɜ (z = 10–83) ɩɨ K-ɫɟɪɢɢ. Ɉɞɧɚɤɨ ɷɬɨ ɪɚɡɪɟɲɟɧɢɟ
ɡɧɚɱɢɬɟɥɶɧɨ ɯɭɠɟ ɞɨɫɬɢɝɚɟɦɨɝɨ ɫ ɩɨɦɨɳɶɸ ɤɪɢɫɬɚɥɥɨɜ-ɚɧɚɥɢɡɚɬɨɪɨɜ (~10 ɷȼ).
ɉɨɞɤɥɸɱɟɧɢɟ ɤɨɦɩɶɸɬɟɪɚ ɩɨɡɜɨɥɹɟɬ ɫɪɚɡɭ ɩɨɥɭɱɚɬɶ ɫɨɞɟɪɠɚɧɢɟ
ɷɥɟɦɟɧɬɚ ɜ ɩɪɨɰɟɧɬɚɯ. ȼɚɠɧɟɣɲɢɦ ɩɪɟɢɦɭɳɟɫɬɜɨɦ ɉɉȾ ɹɜɥɹɟɬɫɹ
ɜɨɡɦɨɠɧɨɫɬɶ ɨɞɧɨɜɪɟɦɟɧɧɨɣ ɪɟɝɢɫɬɪɚɰɢɢ ɪɟɧɬɝɟɧɨɜɫɤɨɝɨ ɢɡɥɭɱɟɧɢɹ ɨɬ
ɜɫɟɯ ɷɥɟɦɟɧɬɨɜ ɫ ɚɬɨɦɧɵɦ ɧɨɦɟɪɨɦ ɜɵɲɟ, ɱɟɦ ɭ ɮɬɨɪɚ. ɂɫɩɨɥɶɡɨɜɚɧɢɟ
ɉɉȾ ɤɨɧɫɬɪɭɤɬɢɜɧɨ ɝɨɪɚɡɞɨ ɩɪɨɳɟ, ɱɟɦ ɤɪɢɫɬɚɥɥɚ-ɚɧɚɥɢɡɚɬɨɪɚ.
Ɉɩɪɟɞɟɥɟɧɢɟ ɤɨɥɢɱɟɫɬɜɟɧɧɨɝɨ ɫɨɫɬɚɜɚ ɨɫɧɨɜɚɧɨ ɧɚ ɢɡɦɟɪɟɧɢɢ
ɫɨɨɬɧɨɲɟɧɢɹ ɢɧɬɟɧɫɢɜɧɨɫɬɟɣ ɪɟɧɬɝɟɧɨɜɫɤɢɯ ɥɢɧɢɣ, ɢɫɩɭɫɤɚɟɦɵɯ
ɨɛɪɚɡɰɨɦ ɢ ɷɬɚɥɨɧɨɦ ɢɡɜɟɫɬɧɨɝɨ ɫɨɫɬɚɜɚ. ȼ ɪɟɡɭɥɶɬɚɬɵ ɢɡɦɟɪɟɧɢɣ
ɧɟɨɛɯɨɞɢɦɨ ɜɧɨɫɢɬɶ ɚɩɩɚɪɚɬɭɪɧɵɟ ɩɨɩɪɚɜɤɢ, ɡɚɜɢɫɹɳɢɟ ɨɬ ɯɚɪɚɤɬɟɪɢɫɬɢɤ
ɢɡɦɟɪɢɬɟɥɶɧɵɯ ɫɢɫɬɟɦ, ɢ ɭɱɢɬɵɜɚɬɶ ɢɧɬɟɧɫɢɜɧɨɫɬɶ ɮɨɧɚ, ɝɥɚɜɧɵɦ
ɢɫɬɨɱɧɢɤɨɦ ɤɨɬɨɪɨɝɨ ɹɜɥɹɟɬɫɹ ɬɨɪɦɨɡɧɨɟ ɪɟɧɬɝɟɧɨɜɫɤɨɟ ɢɡɥɭɱɟɧɢɟ.
ɂɫɩɪɚɜɥɟɧɧɵɟ ɬɚɤɢɦ ɨɛɪɚɡɨɦ ɢɧɬɟɧɫɢɜɧɨɫɬɢ ɩɟɪɟɫɱɢɬɵɜɚɸɬ ɜ
ɤɨɧɰɟɧɬɪɚɰɢɸ ɷɥɟɦɟɧɬɚ ɜ ɚɧɚɥɢɡɢɪɭɟɦɨɣ ɬɨɱɤɟ, ɜɜɨɞɹ ɪɚɡɥɢɱɧɵɟ
ɩɨɩɪɚɜɤɢ, ɭɱɢɬɵɜɚɸɳɢɟ ɜɥɢɹɧɢɟ ɦɚɬɪɢɰɵ.
ȿɫɥɢ ɤɨɧɰɟɧɬɪɚɰɢɹ ɚɧɚɥɢɡɢɪɭɟɦɨɝɨ ɷɥɟɦɟɧɬɚ ɜ ɷɬɚɥɨɧɟ ɢɡɜɟɫɬɧɚ, ɬɨ
ɩɪɢɛɥɢɡɢɬɟɥɶɧɚɹ ɤɨɧɰɟɧɬɪɚɰɢɹ ɷɥɟɦɟɧɬɚ ɜ ɨɛɪɚɡɰɟ ɪɚɫɫɱɢɬɵɜɚɟɬɫɹ ɩɨ
ɮɨɪɦɭɥɟ:
0
0
I
I
CC
c
,
(5.1)
ɝɞɟ C', ɋ
0
– ɤɨɧɰɟɧɬɪɚɰɢɹ ɷɥɟɦɟɧɬɚ ɜ ɨɛɪɚɡɰɟ ɢ ɷɬɚɥɨɧɟ ɫɨɨɬɜɟɬɫɬɜɟɧɧɨ;
I, I
0
– ɢɧɬɟɧɫɢɜɧɨɫɬɢ ɪɟɧɬɝɟɧɨɜɫɤɨɣ ɥɢɧɢɢ, ɩɨɥɭɱɟɧɧɨɣ ɨɬ ɨɛɪɚɡɰɚ ɢ
ɷɬɚɥɨɧɚ ɫɨɨɬɜɟɬɫɬɜɟɧɧɨ.
ɂɫɬɢɧɧɚɹ ɤɨɧɰɟɧɬɪɚɰɢɹ ɷɥɟɦɟɧɬɚ ɜ ɨɛɪɚɡɰɟ ɪɚɜɧɚ:
0
0
F
F
CC
c
,
(5.2)
ɝɞɟ F, F
0
– ɦɚɬɪɢɱɧɵɟ ɩɨɩɪɚɜɤɢ ɨɛɪɚɡɰɚ ɢ ɷɬɚɥɨɧɚ ɫɨɨɬɜɟɬɫɬɜɟɧɧɨ.
Ɉɛɳɚɹ ɩɨɩɪɚɜɤɚ ɨɛɪɚɡɰɚ ɢ ɷɬɚɥɨɧɚ ɜɵɪɚɠɚɟɬɫɹ ɫɨɨɬɧɨɲɟɧɢɟɦ:
F=F
a
×F
ɜ
×F
F
×F
f
×F
s
,
ɝɞɟ F
a
– ɩɨɩɪɚɜɤɚ ɧɚ ɩɨɝɥɨɳɟɧɢɟ ɪɟɧɬɝɟɧɨɜɫɤɨɝɨ ɢɡɥɭɱɟɧɢɹ ɩɪɢ ɜɵɯɨɞɟ ɢɡ
ɨɛɪɚɡɰɚ;
F
ɜ
– ɩɨɩɪɚɜɤɚ ɧɚ ɨɛɪɚɬɧɨɟ ɪɚɫɫɟɹɧɢɟ ɱɚɫɬɢ ɷɥɟɤɬɪɨɧɨɜ;
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