Dresden 2011 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 12: Quantum Dots and Wires: Arsenides

HL 12.6: Talk

Monday, March 14, 2011, 13:15–13:30, POT 151

Fabrication and optical properties of GaAs quantum dots by filling of self-assembled nanoholes — •David Sonnenberg, Andreas Graf, Christian Heyn, and Wolfgang Hansen — Institut für Angewandte Physik, Universität Hamburg, 20355 Hamburg, Germany

We study a novel type of GaAs quantum dots (QDs), which are formed by filling of self-assembled nanoholes in semiconductor surfaces during molecular beam epitaxy. Here, we report on the fabrication and optical properties of these QDs. In our case, the local droplet etching (LDE) process is started with the generation of Al droplets on the AlAs surface. Using appropriate process temperatures, nanoholes are drilled beneath the liquid droplets into the substrates. After drilling, the holes were partially filled with GaAs in order to create strain-free GaAs QDs. The only partial filling results in highly uniform QDs with size precisely controlled by the filling level [1]. The generation of very homogeneous QD ensembles is demonsrated by photoluminescence (PL) linewiths of less than 10 meV. Micro-PL measurements of single QDs show sharp excitonic lines and linewiths combarable to the established InAs QDs [2]. We discuss here PL measurements on single and ensembles of LDE GaAs QDs as function of the QD size.

[1] Heyn et al., Appl. Phys. Let. 94, 183113 (2009)

[2] Heyn et al., Nanoscale Res. Lett. (2010) 5:1633-1636