High-efficiency optical gain in Type-II semiconductor nanocrystals of alloyed colloidal quantum wells
Yükleniyor...
Dosyalar
Tarih
2017
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Amer Chemical Soc
Erişim Hakkı
info:eu-repo/semantics/openAccess
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.
Açıklama
Anahtar Kelimeler
Colloidal Nanocrystals, Type-II, Type-II Semiconductor Nanocrystals, Alloyed Colloidal Quantum Wells
Kaynak
Journal Of Physical Chemistry Letters
WoS Q Değeri
Q1
Scopus Q Değeri
Q1
Cilt
8
Sayı
21
