Impact of Phonons on Dephasing of Individual Excitons in Deterministic Quantum Dot Microlenses

详细信息    查看全文

• 作者：Tomasz Jakubczyk ; Valentin Delmonte ; Sarah Fischbach ; Daniel Wigger ; Doris E. Reiter ; Quentin Mermillod ; Peter Schnauber ; Arsenty Kaganskiy ; Jan-Hindrik Schulze ; André Strittmatter ; Sven Rodt ; Wolfgang Langbein ; Tilmann Kuhn ; Stephan Reitzenstein ; Jacek Kasprzak
• 刊名：ACS Photonics
• 出版年：2016
• 出版时间：December 21, 2016
• 年：2016
• 卷：3
• 期：12
• 页码：2461-2466
• 全文大小：551K
• ISSN：2330-4022

文摘

Optimized light–matter coupling in semiconductor nanostructures is a key to understand their optical properties and can be enabled by advanced fabrication techniques. Using in situ electron beam lithography combined with a low-temperature cathodoluminescence imaging, we deterministically fabricate microlenses above selected InAs quantum dots (QDs), achieving their efficient coupling to the external light field. This enables performing four-wave mixing microspectroscopy of single QD excitons, revealing the exciton population and coherence dynamics. We infer the temperature dependence of the dephasing in order to address the impact of phonons on the decoherence of confined excitons. The loss of the coherence over the first picoseconds is associated with the emission of a phonon wave packet, also governing the phonon background in photoluminescence (PL) spectra. Using theory based on the independent boson model, we consistently explain the initial coherence decay, the zero-phonon line fraction, and the line shape of the phonon-assisted PL using realistic quantum dot geometries.