15 September 2016 Growth technique and effect of post growth annealing on the optical properties of In(Ga)As/GaAs quantum dot heterostructures
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In this paper, we have proposed a technique to maintain the constant overgrowth percentage of quantum dots (QDs) in all layers of a multistacked heterostructure and hence the dot size uniformity is achieved. Two samples have been grown and compared in terms of their optical properties. Post growth annealing was carried out to observe the variation in their properties. The active layer of sample A is composed of 2.7 monolayer (ML) InAs QDs and the QD deposition amount is same for all the stacks. For the proposed sample B, 8ML In(Ga)As QDs were grown as seed layer, and the subsequent QD deposition is kept constant at 5ML. The overgrowth percentage in all QD layers were constant (∼40%) for this sample. Monomodal photoluminescence (PL) emission spectra was observed for the proposed sample B, whereas sample A has multimodal spectra. The samples were subjected to post growth annealing in argon atmosphere for 650, 700, 750, 800, 850, and 900°C. A negligible shift in the PL peak was observed for sample B up to 750°C, which confirms better thermal stability. The PL activation energy variation with respect to the annealed temperature was negligible for the proposed sample B (∼ 165 meV up to 750 °C). Hence the proposed growth mode of In(Ga)As multistacked QD heterostructure has better optical characteristics than the conventional structure in terms of PL spectra, FWHM, and also activation energy.
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Debiprasad Panda, Debiprasad Panda, Aijaz Ahmad, Aijaz Ahmad, Sourav Adhikary, Sourav Adhikary, Hemant Ghadi, Hemant Ghadi, Subhananda Chakrabarti, Subhananda Chakrabarti, } "Growth technique and effect of post growth annealing on the optical properties of In(Ga)As/GaAs quantum dot heterostructures", Proc. SPIE 9927, Nanoengineering: Fabrication, Properties, Optics, and Devices XIII, 99271I (15 September 2016); doi: 10.1117/12.2238605; https://doi.org/10.1117/12.2238605

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