Guided self-assembly of lateral InAs/GaAs quantum-dot molecules for single molecule spectroscopy

• 發表在: Nanoscale Research Letters
• Main Authors: Krause B, Metzger TH, Wang L, Rastelli A, Kiravittaya S, Songmuang R, Schmidt OG
• 格式: Article
• 語言: 英语
• 出版: SpringerOpen 2006-01-01
• 主題: Lateral quantum-dot molecules; Quantum dots; Quantum dot composition; Self-assembled growth
• 在線閱讀: http://dx.doi.org/10.1007/s11671-006-9003-y
• ISSN: 1931-7573; 1556-276X

<p>Abstract</p> <p>We report on the growth and characterization of lateral InAs/GaAs (001) quantum-dot molecules (QDMs) suitable for single QDM optical spectroscopy. The QDMs, forming by depositing InAs on GaAs surfaces with self-assembled nanoholes, are aligned along the [<inline-formula><graphic file="1556-276X-1-74-i1.gif"/></inline-formula>] direction. The relative number of isolated single quantum dots (QDs) is substantially reduced by performing the growth on GaAs surfaces containing stepped mounds. Surface morphology and X-ray measurements suggest that the strain produced by InGaAs-filled nanoholes superimposed to the strain relaxation at the step edges are responsible for the improved QDM properties. QDMs are Ga-richer compared to single QDs, consistent with strain- enhanced intermixing. The high optical quality of single QDMs is probed by micro-photoluminescence spectroscopy in samples with QDM densities lower than 10⁸ cm^&#8722;2.</p>