The InAs/InP quantum dots (QDs) are investigated by time-integrated (PL) and timeresolved photoluminescence (TRPL) experiments. The QDs are fabricated site-selectively by droplet epitaxy technique using block copolymer lithography. The estimated QDs surface density is ∼1.5 × 1010 cm−2 . The PL emission at T = 300 K is centered at 1.5 µm. Below T = 250 K, the PL spectrum shows a fine structure consisting of emission modes attributed to the multimodal QDs size distribution. Temperature-dependent PL reveals negligible carrier transfer among QDs, suggesting good carrier confinement confirmed by theoretical calculations and the TRPL experiment. The PL intensity quench and related energies imply the presence of carrier losses among InP barrier states before carrier capture by QD states. The TRPL experiment highlighted the role of the carrier reservoir in InP. The elongation of PL rise time with temperature imply inefficient carrier capture from the reservoir to QDs. The TRPL experiment at T = 15 K reveals the existence of two PL decay components with strong dispersion across the emission spectrum. The decay times dispersion is attributed to different electron-hole confinement regimes for the studied QDs within their broad distribution affected by the size and chemical content inhomogeneities.
Bibliographical noteFunding Information:
Funding: This research was funded by the Villum Fonden via the NATEC Centre of Excellence under Grant No. 8692 and YIP QUEENs under Grant No. VKR023442. P.H. was funded by the National Science Centre (Poland) within the Etiuda 8 scholarship (Grant No. 2020/36/T/ST5/00511) and by the European Union under the European Social Fund. A.M. was funded by the National Science Centre (Poland) under Grant No. 2014/15/N/ST7/04708.
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- Quantum dots
- Site-selective growth