Документ взят из кэша поисковой машины. Адрес оригинального документа : http://semiconductors.phys.msu.ru/publ/excitons.pdf Дата изменения: Sat Sep 28 22:55:32 2002 Дата индексирования: Mon Oct 1 20:30:23 2012 Кодировка:

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EXCITONS CEASE TO BE EXOTIC QUASIPARTICLES
V . S. DNEPRO V SKII

The enhancement of both the binding energy and the oscillator strength of excitons in nanostructures and the possibility to increase the strength of Coulomb interaction, responsible for the binding of electron­hole pairs to excitons, by combining semiconductor and dielectric materials with different values of dielectric constants allow to create excitonic devices operating at room temperature. , , ­ , , .
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(). ( ) . , ­ , , ­, . , () , , , . , , , . ­ . , , , . (. 1). . , , E

, , ­ . "" (). , ­ , . , M = me + mh , me, h ­ (). µ (µ memh /(me + mh) ­ - ) . , , , , E
3D ex

eµ e = ------------2 = ------------ , 2 2 a ex 2
4 2

(1)

( ) a ex = ------- , 2 eµ
2

(2)

e ­ , ­ , 3D ( ). ,
3D 1 E = ­ E ex ---- , 2 n

C n=2 E n=1 Eg
3D ex

(3)

V . 1. . Eg ­ ( V C )

n ­ , . > 10, () , (1) (2) , ­ . , , E = e4m /(2 2) 13,5 (m ­ ). . GaAs Eex 4,2 , aex 15 . ,

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kT 26 T = 300 K (k ­ ). , , ( ) - , 3 V 0 / a ex , V0 ­ (aex V0). , , : 1) , 2) ( ) - . ? , , , aex . , ( d aex), E
2D n



R

p 1 GaAlAs n 2 h

- +

GaAs i

. 2. ­ , ­ (1 ) 105 / (2 )

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E = ­ ------------------2 . 1 n ­ -- 2

3D ex

(4)

, 2D- ( 2D E n (4) n = 1) 4 , ( ). , , . , . . (. 2, ) ( ) ­ ( 10 ) GaAs, GaAlAs. (!) (. 2, ). , , -

90

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. ( !) ( 10-12 ) , . (300 K) - ­ (kT 26 ) ( 10 ) . , (- ), (. 2, ). - p­i­n , i- . R . , i- . - (. 2, ). , , , . - , . ( , . 2, ), , , . . : , [1], ( SEED ­ Self-Electrooptic Effect Device). , , . d aex ( E
1D ex

[1]. - () , . ­ - . ­ ­ , , (s > 10) (. (1)­(4)). , , ­ " ". (. 3). , , , d s . , z (s /d)ds , ds ­ , F e2 /(d z2). ­ (!), , . , 3D 3 / 2 3D ( a ex > d s > ( d / s ) a ex ) , E ex > 100 s 1 / 2 1 ­1 / 2 -- ln --- ( s d ) [2], d d
1D

[ ln ( d / a ex ) ] ) ,
2 ­1

( l ex ln ( d / a ex ) ) [2].

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91




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­ , , . ­ ( ). ­ . [4, 5].
1. Kelly M.J. Low-Dimensional Semiconductors: Materials, Physics, Technology, Devices. Oxford: Clarendon Press, 1995. 2. Keldysh L.V. Excitons in Semiconductor­Dielectric Nanostructures // Phys. status solidi. 1997. Vol. 164, 3. 3. .., .., .., .. , // . 1998. . 113. . 4. .. // . 1997. 5. . 93­99. 5. .. , , . ? // . . 80­86.

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3D 8 / 3

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, , , . . ­ , , . 200 .

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