High optical quality site-controlled quantum dots

• Published in: Microelectronic engineering 2010-05, Vol.87 (5), p.1357-1359
• Main Authors: Pfau, T.J., Gushterov, A., Reithmaier, J.P., Cestier, I., Eisenstein, G.
• Format: Article
• Language: English
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Electronics; Exact sciences and technology; Gallium arsenide; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Microelectronic fabrication (materials and surfaces technology); Molecular beam epitaxy; Molecular electronics, nanoelectronics; Molecular, atomic, ion, and chemical beam epitaxy; Nanoscale materials and structures: fabrication and characterization; Physics; Pre-patterned surface; Quantum dot stack; Quantum dots; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Single photon source; Site-controlled growth; Thin buffer layers; Wet-chemical etching
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2009.12.033

GaAs substrates were pre-patterned by electron beam (e-beam) lithography and wet-chemically etched holes. The hole structures, presented here, enable growth of site-controlled InAs quantum dots with low dot density in the range of 10 8 cm −2 by molecular beam epitaxy (MBE). In order to reduce defect related non-radiative recombination processes at the etched surface, wet-chemical etching and a modified growth of stacked quantum dot layers are developed. The total buffer layer thickness could be increased to 55 nm GaAs by only one overgrowth step of a quantum dot seed layer in comparison to strain-coupled multi-stacked structure with typically 10 nm buffer layer thickness between each stack.