Optical properties of individual site-controlled Ge quantum dots

Journal Article · Mon Jun 22 00:00:00 EDT 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4923188· OSTI ID:22483088

Grydlik, Martyna ^[1]; Brehm, Moritz ^[1]; Tayagaki, Takeshi ^[2]; Langer, Gregor; Schäffler, Friedrich ^[1]; Schmidt, Oliver G. ^[3]

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1. Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz (Austria)
2. Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan)
3. Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, Dresden 01069 (Germany)

We report photoluminescence (PL) experiments on individual SiGe quantum dots (QDs) that were epitaxially grown in a site-controlled fashion on pre-patterned Si(001) substrates. We demonstrate that the PL line-widths of single QDs decrease with excitation power to about 16 meV, a value that is much narrower than any of the previously reported PL signals in the SiGe/Si heterosystem. At low temperatures, the PL-intensity becomes limited by a 25 meV high potential-barrier between the QDs and the surrounding Ge wetting layer (WL). This barrier impedes QD filling from the WL which collects and traps most of the optically excited holes in this type-II heterosystem.

• OSTI ID: 22483088
• Journal Information: Applied Physics Letters, Vol. 106, Issue 25; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
EPITAXY
EXCITATION
GERMANIUM SILICIDES
LAYERS
LINE WIDTHS
MEV RANGE 10-100
OPTICAL PROPERTIES
PHOTOLUMINESCENCE
POTENTIALS
QUANTUM DOTS
SIGNALS
SUBSTRATES
TRAPS