High-Efficiency Optical Gain in Type-II Semiconductor Nanocrystals of Alloyed Colloidal Quantum Wells

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Guzelturk B., Kelestemur Y., Olutas M., Li Q., Lian T., Demir H. V.

JOURNAL OF PHYSICAL CHEMISTRY LETTERS, cilt.8, sa.21, ss.5317-5324, 2017 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 8 Sayı: 21
  • Basım Tarihi: 2017
  • Doi Numarası: 10.1021/acs.jpclett.7b02367
  • Dergi Adı: JOURNAL OF PHYSICAL CHEMISTRY LETTERS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.5317-5324
  • Orta Doğu Teknik Üniversitesi Adresli: Hayır

Özet

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 mu J/cm(2), long optical gain lifetimes (tau(gain) approximate to 400 ps), and high modal gain coefficients (g(modal) approximate to 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.