Highly uniform and strain-free GaAs quantum dots fabricated by filling of self-assembled nanoholes

• Published in: Applied physics letters Vol. 94; no. 18
• Main Authors: Heyn, Ch, Stemmann, A., Köppen, T., Strelow, Ch, Kipp, T., Grave, M., Mendach, S., Hansen, W.
• Format: Journal Article
• Language: English
• Published: United States 04-05-2009
• Subjects: ALUMINIUM ARSENIDES; ANISOTROPY; CRYSTAL GROWTH; DROPLETS; ELECTRONS; ETCHING; FINE STRUCTURE; GALLIUM ARSENIDES; MOLECULAR BEAM EPITAXY; NANOSCIENCE AND NANOTECHNOLOGY; PHOTOLUMINESCENCE; QUANTUM DOTS; SEMICONDUCTOR MATERIALS
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.3133338

We demonstrate the self-assembled creation of a novel type of strain-free semiconductor quantum dot (QD) by local droplet etching (LDE) with Al to form nanoholes in AlGaAs or AlAs surfaces and subsequent filling with GaAs. Since the holes are filled with a precisely defined filling level, we achieve ultrauniform LDE QD ensembles with extremely narrow photoluminescence (PL) linewidth of less than 10 meV. The PL peaks agree with a slightly anisotropic parabolic potential. Small QDs reveal indications for transitions between electron and hole states with different quantization numbers. For large QDs, a very small fine-structure splitting is observed.