Optical anisotropy and the direction of polarization of exciton emissions in a semiconductor quantum dot: Effect of heavy- and light-hole mixing. (August 2017)

• Record Type: Journal Article
• Authors: Singh, Ranber; Kumar, Rajiv; Singh, Vikramjeet
• Is Part Of: Chinese physics B. Volume 26:Number 8(2017)
• Publication Date: 2017-08
• Subjects: light-heavy hole mixing -- excitons -- quantum dots; 73.21.La -- 78.67.Hc; Physics -- Periodicals; Physics; Periodicals; 530.05
• DOI: 10.1088/1674-1056/26/8/087303
• Languages: English
• ISSNs: 1674-1056

Abstract

Abstract : The dependence of the directions of polarization of exciton emissions, fine structure splittings (FSS), and polarization anisotropy on the light- and heavy-hole (LH–HH) mixing in semiconductor quantum dots (QDs) is investigated using a mesoscopic model. In general, all QDs have a four-fold exciton ground state. Two exciton states have directions of polarization in the growth-plane, while the other two are along the growth direction of the QD. The LH–HH mixing does affect the FSS and polarization anisotropy of bright exciton states in the growth-plane in the low symmetry QDs (e.g., C 2 V, CS, C 1 ), while it has no effect on the FSS and polarization anisotropy in high symmetry QDs (e.g., C 3 V, D 2 d ). When the hole ground state is pure HH or LH, the bright exciton states in the growth-plane are normal to each other. The LH–HH mixing affects the relative intensities and directions of bright exciton states in the growth-plane of the QD. The polarization anisotropy of exciton emissions in the growth-plane of the QD is independent of the phase angle of LH–HH mixing but strongly depends on the magnitude of LH–HH mixing in low symmetry QDs.