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Interdot carrier and spin dynamics in a two-dimensional high-density quantum-dot array of InGaAs with quantum dots embedded as local potential minima

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Title: Interdot carrier and spin dynamics in a two-dimensional high-density quantum-dot array of InGaAs with quantum dots embedded as local potential minima
Authors: Hiura, Satoshi Browse this author
Urabe, Masayuki Browse this author
Takeishi, Kazuki Browse this author
Itabashi, Kodai Browse this author
Takayama, Junichi Browse this author
Kiba, Takayuki Browse this author
Sueoka, Kazuhisa Browse this author →KAKEN DB
Murayama, Akihiro Browse this author →KAKEN DB
Keywords: quantum dots
InGaAs
carrier dynamics
spin dynamics
laterally coupled quantum dots
carrier transfer
Issue Date: Feb-2019
Publisher: IOP Publishing
Journal Title: Semiconductor science and technology
Volume: 34
Issue: 2
Start Page: 025001
Publisher DOI: 10.1088/1361-6641/aaf7aa
Abstract: Interdot carrier and spin dynamics were studied in a two-dimensional array of high-density small quantum dots (SQDs) of InGaAs with an average diameter of 16 nm and a sheet density of 1.2 x 10(11) cm(-2), in which 24 nm diametric large QDs (LQDs) were embedded as local potential minima. We observed a delayed photoluminescence (PL) rise from the lower-lying LQD states and a considerably faster PL decay from the higher-lying SQD states, indicating carrier transfer from the two-dimensionally coupled SQDs into the LQDs. In addition, inverse carrier tunneling from the LQDs into the SQDs was thermally induced, which is characterized by the thermal activation energy between the LQDs and SQDs. Moreover, circularly polarized transient PL behavior from the SQD states exhibits a suppression of the spin polarization decay in the initial time region, depending on the excited spin density. This tentatively suppressed spin relaxation can be quantitatively explained by selective interdot transfer of minority-spin electrons from the SQDs into LQDs, when the majority spin states in both QDs are sufficiently populated by excited spins. These findings indicate that the high-density SQDs behave as the main emitters with suppressed spin relaxation, while the scattered LQDs with lower potential behave as the receivers of minority-spin electrons.
Rights: This is a peer-reviewed, un-copyedited version of an article accepted for publication/published in Semiconductor Science and Technology, Volume 34, Number 2. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1361-6641/aaf7aa.
https://creativecommons.org/licenses/by-nc-nd/3.0/
Type: article (author version)
URI: http://hdl.handle.net/2115/76671
Appears in Collections:情報科学院・情報科学研究院 (Graduate School of Information Science and Technology / Faculty of Information Science and Technology) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

Submitter: 樋浦 諭志

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