Time-resolved intraband relaxation of strongly confined electrons and holes in colloidal PbSe nanocrystals

被引：132
作者：
Harbold, JM [1 ]
Du, H
Krauss, TD
Cho, KS
Murray, CB
Wise, FW
机构：
[1] Cornell Univ, Dept Appl Phys, Ithaca, NY 14853 USA
[2] Univ Rochester, Dept Chem, Rochester, NY 14627 USA
[3] IBM Corp, Thomas J Watson Res Ctr, Yorktown Hts, NY 10598 USA
来源：
PHYSICAL REVIEW B | 2005年 / 72卷 / 19期
关键词：
D O I：
10.1103/PhysRevB.72.195312
中图分类号：
T [工业技术];
学科分类号：
08 ;
摘要：
The relaxation of strongly confined electrons and holes from higher excited states to their lowest excited states in colloidal PbSe nanocrystals has been time resolved using femtosecond transient absorption spectroscopy. In contrast to II-VI and III-V semiconductor nanocrystals, both electrons and holes are strongly confined in PbSe nanocrystals. Despite the large electron and hole energy level spacings (at least 12 times the optical phonon energy), we consistently observe picosecond time-scale relaxation. Existing theories of carrier relaxation cannot account for these experimental results. We conjecture about mechanisms that could circumvent the expected phonon bottleneck in IV-VI quantum dots.
引用
收藏
页数：6
相关论文
共 28 条
[1]   Confinement effects in PbSe quantum wells and nanocrystals [J].
Allan, G ;
Delerue, C .
PHYSICAL REVIEW B, 2004, 70 (24) :1-9
[2]  
ALLAN G, COMMUNICATION
[3]   Anisotropy-induced optical transitions in PbSe and PbS spherical quantum dots [J].
Andreev, AD ;
Lipovskii, AA .
PHYSICAL REVIEW B, 1999, 59 (23) :15402-15404
[4]   INTRINSIC MECHANISM FOR THE POOR LUMINESCENCE PROPERTIES OF QUANTUM-BOX SYSTEMS [J].
BENISTY, H ;
SOTOMAYORTORRES, CM ;
WEISBUCH, C .
PHYSICAL REVIEW B, 1991, 44 (19) :10945-10948
[5]   Electron relaxation in colloidal InP quantum dots with photogenerated excitons or chemically injected electrons [J].
Blackburn, JL ;
Ellingson, RJ ;
Micic, OI ;
Nozik, AJ .
JOURNAL OF PHYSICAL CHEMISTRY B, 2003, 107 (01) :102-109
[6]   PHONON-SCATTERING AND ENERGY RELAXATION IN 2-DIMENSIONAL, ONE-DIMENSIONAL, AND ZERO-DIMENSIONAL ELECTRON GASES [J].
BOCKELMANN, U ;
BASTARD, G .
PHYSICAL REVIEW B, 1990, 42 (14) :8947-8951
[7]   Why is the thermalization of excited electrons in semiconductor nanoparticles so rapid? Studies on CdSe nanoparticles [J].
Darugar, Q ;
Landes, C ;
Link, S ;
Schill, A ;
El-Sayed, MA .
CHEMICAL PHYSICS LETTERS, 2003, 373 (3-4) :284-291
[8]   Optical properties of colloidal PbSe nanocrystals [J].
Du, H ;
Chen, CL ;
Krishnan, R ;
Krauss, TD ;
Harbold, JM ;
Wise, FW ;
Thomas, MG ;
Silcox, J .
NANO LETTERS, 2002, 2 (11) :1321-1324
[9]  
EFROS AL, 1995, SOLID STATE COMMUN, V93, P281, DOI 10.1016/0038-1098(94)00780-2
[10]   Highly efficient multiple exciton generation in colloidal PbSe and PbS quantum dots [J].
Ellingson, RJ ;
Beard, MC ;
Johnson, JC ;
Yu, PR ;
Micic, OI ;
Nozik, AJ ;
Shabaev, A ;
Efros, AL .
NANO LETTERS, 2005, 5 (05) :865-871
123