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      High-efficiency optical gain in type-II semiconductor nanocrystals of alloyed colloidal quantum wells

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      Author(s)
      Guzelturk, B.
      Kelestemur Y.
      Olutas M.
      Li, Q.
      Lian, T.
      Demir, Hilmi Volkan
      Date
      2017
      Source Title
      Journal of Physical Chemistry Letters
      Print ISSN
      1948-7185
      Publisher
      American Chemical Society
      Volume
      8
      Issue
      21
      Pages
      5317 - 5324
      Language
      English
      Type
      Article
      Item Usage Stats
      218
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      345
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      Abstract
      Colloidal nanocrystals having controlled size, tailored shape, and tuned composition have been explored for optical gain and lasing. Among these, nanocrystals having Type-II electronic structure have been introduced toward low-threshold gain. However, to date, their performance has remained severely limited due to diminishing oscillator strength and modest absorption cross-section. Overcoming these problems, here we realize highly efficient optical gain in Type-II nanocrystals by using alloyed colloidal quantum wells. With composition-tuned core/alloyed-crown CdSe/CdSexTe1-x quantum wells, we achieved amplified spontaneous emission thresholds as low as 26 μJ/cm2, long optical gain lifetimes (τgain ≈ 400 ps), and high modal gain coefficients (gmodal ≈ 930 cm-1). We uncover that the optical gain in these Type-II quantum wells arises from the excitations localized to the alloyed-crown region that are electronically coupled to the charge-transfer state. These alloyed heteronanostructures exhibiting remarkable optical gain performance are expected to be highly appealing for future display and lighting technologies.
      Keywords
      Cadmium compounds
      Charge transfer
      Electronic structure
      Nanocrystals
      Optical gain
      Quantum theory
      Absorption cross sections
      Amplified spontaneous emissions
      Charge transfer state
      Colloidal nanocrystals
      Colloidal quantum wells
      Hetero-nanostructures
      Semiconductor nanocrystals
      Type-II quantum wells
      Semiconductor quantum wells
      Permalink
      http://hdl.handle.net/11693/37292
      Published Version (Please cite this version)
      http://dx.doi.org/10.1021/acs.jpclett.7b02367
      Collections
      • Department of Electrical and Electronics Engineering 4011
      • Department of Physics 2550
      • Institute of Materials Science and Nanotechnology (UNAM) 2258
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