Origin of one-photon and two-photon optical transitions in PbSe nanocrystals

被引：16

作者：

Franceschetti, A. ^{[1
]}

Luo, J. W. ^{[1
]}

An, J. M. ^{[1
]}

Zunger, A. ^{[1
]}

机构：

[1] Natl Renewable Energy Lab, Golden, CO 80401 USA

来源：

PHYSICAL REVIEW B | 2009年 / 79卷 / 24期

关键词：

energy gap; IV-VI semiconductors; lead compounds; nanostructured materials; photoluminescence; pseudopotential methods; two-photon spectra; MULTIPLE EXCITON GENERATION; CDSE QUANTUM DOTS; ELECTRONIC-STRUCTURE; COLLOIDAL PBSE; ANISOTROPY; ENERGY; GAP;

D O I：

10.1103/PhysRevB.79.241311

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

PbSe nanocrystals represent the paradigm nanoscale system exhibiting carrier multiplication upon light absorption, yet their absorption spectrum is poorly understood. Two very different interpretations of the absorption peaks have been proposed: is the second absorption peak a dipole-forbidden S(h)-P(e) or P(h)-S(e) transition or a dipole-allowed P(h)-P(e) transition? A recent two-photon photoluminescence-excitation experiment favored the first interpretation, raising the question of why a dipole-forbidden transition would be strongly absorptive. Here we report atomistic pseudopotential calculations of the one-photon and two-photon absorption spectra of PbSe nanocrystals, showing unequivocally that, contrary to previous interpretations by other authors, the second one-photon absorption peak originates from dipole-allowed P(h)-P(e) transitions.

引用

页数：4

共 32 条

[1] Confinement effects in PbSe quantum wells and nanocrystals [J].