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https://doi.org/10.3938/NPSM.69.794
Photoluminescence Study of Type-II Submonolayer Quantum Dots
New Phys.: Sae Mulli 2019; 69: 794~799
Published online August 30, 2019;  https://doi.org/10.3938/NPSM.69.794
© 2019 New Physics: Sae Mulli.

inseak KIN1, Hyun-Jun JO1, Mo Geun SO1, Jong Su KIM1*, Yeongho KIM2, Sang Jun LEE2, Seung Hyun LEE3, Christiana B. HONSBERG4, Heedae KIM5

1Department of Physics, Yeungnam University, Gyeongsan 38541, Korea
2Division of Convergence Technology, Korea Research Institute of Standards and Science, Daejeon 34113, Korea
3Department of Electrical and Computer Engineering, Ohio State University, Columbus, USA
4School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, USA
5School of Physics, Northeast Normal University, Changchun 130024, China
Correspondence to: jongsukim@ynu.ac.kr
Received December 12, 2018; Revised April 22, 2019; Accepted April 22, 2019.
cc This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
We have studied the optical properties of InAs/GaAsSb submonolayer quantum dots (SML-QDs) through excitation intensity ($I_{\text{ex}}$) and temperature dependent photoluminescence (PL) experiments. The SML-QDs with type-I (T-1) and type-II (T-2) band structures were grown using a GaAsSb spacer with a Sb composition of 0\% and 15.8\%. At 13~K, the PL signals from the T-1 and the T-2 samples were observed at 1.42~eV and 1.37~eV, respectively, when the $I_{\text{ex}}$ was 8.7~mW/cm$ ^{2}$. The PL signal of the T-1 sample is due to the recombination of electrons and holes in the InAs SML-QDs. The PL signal of the T-2 sample is due to the recombination of electrons (in the GaAs electron band) and holes (in the GaAsSb spacer hole band) by type-II band alignment formed between GaAs and GaAsSb. The full widths at half maxima (FWHMs) of the T-1 and the T-2 samples were 7.09~meV and 24.6~meV, respectively, because the T-2 sample has a lower uniformity than the T-1 sample. As the excitation intensity was increased, the PL signals of the T-1 and the T-2 samples shifted to lower energy because of the quantum-confined Stark effect. As a result of these temperature-dependent PL experiments, the activation energy of the T-1 sample was found to be 30~meV.
PACS numbers: 73.21.La, 78.55.-m, 71.55.Eq
Keywords: Submonolayer, Quasimonolayer, III-V semiconductor, Quantum dot, Photoluminescence


August 2019, 69 (8)
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