title: Optical characterization of In-flushed InAs/GaAs quantum dots emitting a broadband spectrum with multiple peaks at ~1 μm.
abstract: We investigated optical properties of In-flushed InAs quantum dots (QDs) grown on a GaAs substrate by molecular beam epitaxy. By using the In-flush technique for setting the height of self-assembled InAs QDs, we have tuned the emission wavelength of InAs QDs to the ~1 μm regime, which can be utilized as a non-invasive and deeply penetrative probe for biological and medical imaging systems. The controlled emission exhibited a broadband spectrum comprising multiple peaks with an interval of approximately 30 meV. We examined the origin of the multiple peaks using spectral and time-resolved photoluminescence, and concluded that it is attributed to monolayer step fluctuations in the height of the In-flushed QDs. This feature can be advantageous for realizing a broadband light source centered at the ~1 μm regime, which is especially suitable for the non-invasive cross-sectional biological and medical imaging system known as optical coherence tomography.
authors.affiliation: Graduate School of Engineering, University of Fukui, Fukui, 910-8507 Japan.
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Kitamura
authors.affiliation: Graduate School of Engineering, University of Fukui, Fukui, 910-8507 Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Senshu
authors.affiliation: Graduate School of Engineering, University of Fukui, Fukui, 910-8507 Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Katsuyama
authors.affiliation: Faculty of Systems Engineering, Wakayama University, Wakayama, 640-8510 Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hino
authors.affiliation: Faculty of Systems Engineering, Wakayama University, Wakayama, 640-8510 Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Ozaki
authors.affiliation: NEC Corporation, Tsukuba, Ibaraki 305-8501 Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Ohkouchi
authors.affiliation: National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0047 Japan.
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Sugimoto
authors.affiliation: Department Electronic and Electrical Eng, University of Sheffield, Sheffield, S3 7HQ UK.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Hogg
keywords: Broadband light source; In-flush; MBE; OCT; Quantum dot; Time-resolved PL