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

Guzelturk, Burak
Keleştemur, Yusuf
Olutas, Murat
Li, Quyang
Lian, Tianquan
Demir, Hilmi Volkan
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.


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Citation Formats
B. Guzelturk, Y. Keleştemur, M. Olutas, Q. Li, T. Lian, and H. V. Demir, “High-Efficiency Optical Gain in Type-II Semiconductor Nanocrystals of Alloyed Colloidal Quantum Wells,” JOURNAL OF PHYSICAL CHEMISTRY LETTERS, vol. 8, no. 21, pp. 5317–5324, 2017, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/92398.