Growth of Novel GaAs QDs in AlGaAs Matrix

Date

Jun 21, 2013

Time

1:00 PM - 2:00 PM

Speaker

Dr. Yongheng Huo

Affiliation

IFW Dresden

Language

en

Main Topic

Materialien

Other Topics

Materialien, Physik

Host

Ulrike Steere

Description

GaAs quantum dot (QD) has attracted much attention since compared with the generally used SK QDs it can offer a ‘clean’ environment for studying fundamental physics of QDs [1]. Its emission properties can be tuned to resonant with that of rubidium atomic vapor which enables a hybrid atomic-solid state interface in quantum information applications as quantum memories and repeaters [2]. However, GaAs QDs grown by droplet epitaxy and filling local droplet etched holes generally have a broad linewidth (~60 &#956;eV) and big fine structure splitting (FSS) (~30-40 &#956;eV) [3] which limit their real applications. Here we report a systematic study of growing GaAs QDs directly in AlGaAs matrix to improve the optical quality. As in ref [3], we grew QDs by infilling GaAs nanoholes etched in AlGaAs matrix using Al droplet-epitaxy. By optimizing growth parameters, we have obtained low density GaAs QDs (<0.3&#956;m-2) with improved optical quality and symmetry. An average FWHM of the neutron excitonic emission around 23 &#956;eV under non-resonant cw excitation and corresponding average FSS around 4 &#956;eV were demonstrated [4]. By applying biaxial strain on this kind of QDs, we successfully switched light hole to the ground state of valence band. This opens up the way to explore both the fundamental properties and potential applications of three-dimensionally confined light-hole excitons[5]. [1] D. Gammon et al., Phys. Rev. Lett. 76, 3005 (1996). [2] N. Akopian, L. Wang, A. Rastelli, O. G. Schmidt, and V. Zwiller, Nat. Photonic,s 5, 230 (2011). [3] Ch. Heyn, et al., Nanoscale Res. Lett.,,5, 1633 (2010) [4] Y. H. Huo, A. Rastelli, O. G. Schmidt, Appl. Phys. Lett. 102, 152105 (2013)[5] Y. H. Huo, et al., submitted

Links

• Seminars at the IFW

Last modified: Jun 21, 2013, 9:50:59 AM