Carrier multiplication and its reduction by photodoping in colloidal InAs quantum dots

被引：165

作者：

Pijpers, J. J. H.

Hendry, E.

Milder, M. T. W.

Fanciulli, R.

Savolainen, J.

Herek, J. L.

Vanmaekelbergh, D.

Ruhman, S.

Mocatta, D.

Oron, D.

Aharoni, A.

Banin, U.

Bonn, M.

机构：

[1] FOM, Inst Atom & Mol Phys, NL-1098 SJ Amsterdam, Netherlands

[2] Univ Utrecht, Debye Res Inst, Dept Condensed Matter & Interfaces, NL-3508 TA Utrecht, Netherlands

[3] Hebrew Univ Jerusalem, Inst Chem, IL-91904 Jerusalem, Israel

[4] Hebrew Univ Jerusalem, Ctr Nanosci & Nanotechnol, IL-91904 Jerusalem, Israel

来源：

JOURNAL OF PHYSICAL CHEMISTRY C | 2007年 / 111卷 / 11期

关键词：

D O I：

10.1021/jp066709v

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Carrier (exciton) multiplication in colloidal InAs/CdSe/ZnSe core-shell quantum dots (QDs) is investigated using terahertz time-domain spectroscopy, time-resolved transient absorption, and quasi-continuous wave excitation spectroscopy. For excitation by high-energy photons (similar to 2.7 times the band gap energy), highly efficient carrier multiplication (CM) results in the appearance of multi-excitons, amounting to similar to 1.6 excitons per absorbed photon. Multi-exciton recombination occurs within tens of picoseconds via Auger-type processes. Photodoping (i.e., photoinjection of an exciton) of the QDs prior to excitation results in a reduction of the CM efficiency to similar to 1.3. This exciton-induced reduction of CM efficiency can be explained by the twofold degeneracy of the lowest conduction band energy level. We discuss the implications of our findings for the potential application of InAs QDs as light absorbers in solar cells.

引用

页码：4146 / 4152

页数：7

共 40 条

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