Non-radiative recombination at dislocations in InAs quantum dots grown on silicon

Journal Article · Mon Sep 23 00:00:00 EDT 2019 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.5113517· OSTI ID:1613736

Selvidge, Jennifer ^[1]; Norman, Justin ^[2]; Salmon, Michael E. ^[3]; Hughes, Eamonn T. ^[2]; Bowers, John E. ^[4]; Herrick, Robert ^[5]; Mukherjee, Kunal ^[2]

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1. Materials Department, University of California, Santa Barbara, Santa Barbara, California 93106, USA; DOE/OSTI
2. Materials Department, University of California, Santa Barbara, Santa Barbara, California 93106, USA
3. EAG Laboratories–Eurofins Materials Science, 628 Hutton St., Suite 103, Raleigh, North Carolina 27606, USA
4. Materials Department, University of California, Santa Barbara, Santa Barbara, California 93106, USA; Department of Electrical and Computer Engineering, University of California, Santa Barbara, Santa Barbara, California 93106, USA
5. Intel Corporation, Santa Clara, California 95054, USA

We study the impact of misfit dislocations on the luminescence from InAs quantum dots (QDs) grown on Si substrates. Electron channeling contrast imaging is used together with cathodoluminescence mapping to locate misfit dislocations and characterize the resulting nonradiative recombination of carriers via near-infrared light emission profiles. With a 5 kV electron beam probe, the dark line defect width due to a typical misfit dislocation in a shallow QD active layer is found to be approximately 1 μm, with a 40%–50% peak emission intensity loss at room temperature. Importantly, we find that at cryogenic temperatures, the dislocations affect the QD ground state and the first excited state emission significantly less than the second excited state emission. At the same time, the dark line defect width, which partially relates to carrier diffusion in the system, is relatively constant across the temperature range of 10 K–300 K. Our results suggest that carrier dynamics in the QD wetting layer control emission intensity loss at dislocations, and that these defects reduce luminescence only at those temperatures where the probability of carriers thermalizing from the dots into the wetting layer becomes significant. We discuss the implications of these findings toward growing dislocation-tolerant, reliable quantum dot lasers on silicon.

• Research Organization: Columbia Univ., New York, NY (United States)
• Sponsoring Organization: USDOE Advanced Research Projects Agency - Energy (ARPA-E)
• Grant/Contract Number: AR0000843
• OSTI ID: 1613736
• Alternate ID(s): OSTI ID: 1566273
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 13 Vol. 115; ISSN 0003-6951
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

Electron beams
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
Crystallographic defects
Emission spectroscopy
Epitaxy
Lasers
Luminescence
Physics
Quantum dots