10 Si 5 optical phonons impurities 3 acoustic phonons 2 undoped Si 0.5 0.3 Si ([P]1020 cm 3 Soininen,1992 100 300 500 1000 Temperature[K灯
undoped Si Soininen, 1992
Effect diffusion length Lefr 1994年，Britton等人发现，由于晶体缺陷和电场的影响，扩 散长度应修正为： 1 2kgT 2kgT Eim是电场强度.有效扩散长度随电场强度的增加而增加
Effect diffusion length Leff k T E k T eE D L B drift B eff drift eff 2 2 2 1 2 − + = + λ 1994ᑈ, BrittonㄝҎথ⦄, ⬅Ѣԧ㔎䱋⬉എⱘᕅડ,ᠽ ᬷ䭓ᑺᑨׂℷЎ: Edrift ᰃ⬉എᔎᑺ. ᳝ᬜᠽᬷ䭓ᑺ䱣⬉എᔎᑺⱘࡴ㗠ࡴ.
Trapping ☐Vacancies Shallow positron traps ☐Dislocations ☐Voids Precipitates Surfaces ☐Interfaces ☐Graned Material Positronium formation
Vacancies Shallow positron traps Dislocations Voids Precipitates Surfaces Interfaces Graned Material Positronium formation Trapping
Positron Annihilation Lifetime Spectroscopy probability n(t)that e+is alive at time t: dn (1) =-2n(t) n(0)=1 A-positron annihilation rate di Positron lifetime spectrum in bulk: (no trapping of positrons) 10 Si Toulk=219 ps bulk GaAs:Zn rouk=230 ps 10 b= 1 10 n(t)=e-ibuk! annihilation radiation 10 A-slope of the exponential decay 10 0 100 200 300 400 Channels
a-Sn 300 GaSb In.Sb InP IHAs GaAs GaP e Si 200 T=Cao2, 3/2 Beo (C1=543.8ps/nm5) 100 ， Siethoff 1998 Phys.stat.sol.(b)205,R3 0.10.2 0.30.4 0.5 0.6 32 f牡 32
( 543.8 / ) , 1.5 1 3/ 2 1 0 C ps nm C a b = τ = Siethoff 1998 Phys.stat.sol.(b)205,R3