Browsing by Author "Li, Mingjie"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    Article
    Efficient generation of emissive many-body correlations in copper-doped colloidal quantum wells
    (Elsevier, 2022) Yu, Junhong; Sharma, Manoj; Li, Mingjie; Liu, Baiquan; Hernandez-Martinez, Pedro Ludwig; Delikanli, Savas; Sharma, Ashma; Altintas, Yemliha; Hettiarachchi, Chathuranga; Sum, Tze Chien; Demir, Hilmi Volkan; Dang, Cuong; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Altintas, Yemliha
    Colloidal quantum wells (CQWs) provide an appealing platform to achieve emissive many-body correlations for novel optoelectronic devices, given that they act as hosts for strong carrier Coulomb interactions and present suppressed Auger recombination. However, the demonstrated high-order excitonic emission in CQWs requires ultrafast pumping with high excitation levels and can only be spec-trally resolved at the single-particle level under cryogenic condi-tions. Here, through systematic investigation using static power -dependent emission spectroscopy and transient carrier dynamics, we show that Cu-doped CdSe CQWs exhibit continuous-wave -pumped high-order excitonic emission at room temperature with a large binding energy of X64 meV. We attribute this unique behavior to dopant excitons in which the ultralong lifetime and the highly localized wavefunction facilitate the formation of many-body corre-lations. The spectrally resolved high-order excitonic emission gener-ated at power levels compatible with solar irradiation and electrical injection might pave the way for novel solution-processed solid-state devices.
  • Thumbnail Image
    Article
    Low-Threshold Lasing from Copper-Doped CdSe Colloidal Quantum Wells
    (WILEY-V C H VERLAG GMBHPOSTFACH 101161, 69451 WEINHEIM, GERMANY, 2021) Yu, Junhong; Sharma, Manoj; Li, Mingjie; Delikanli, Savas; Sharma, Ashma; Taimoor, Muhammad; Altintas, Yemliha; McBride, James R.; Kusserow, Thomas; Sum, Tze-Chien; Demir, Hilmi Volkan; Dang, Cuong; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Altintas, Yemliha
    Transition metal doped colloidal nanomaterials (TMDCNMs) have recently attracted attention as promising nano-emitters due to dopant-induced properties. However, despite ample investigations on the steady-state and dynamic spectroscopy of TMDCNMs, experimental understandings of their performance in stimulated emission regimes are still elusive. Here, the optical gain properties of copper-doped CdSe colloidal quantum wells (CQWs) are systemically studied with a wide range of dopant concentration for the first time. This work demonstrates that the amplified spontaneous emission (ASE) threshold in copper-doped CQWs is a competing result between the biexciton formation, which is preferred to achieve population inversion, and the hole trapping which stymies the population inversion. An optimum amount of copper dopants enables the lowest ASE threshold of approximate to 7 mu J cm(-2), about 8-fold reduction from that in undoped CQWs (approximate to 58 mu J cm(-2)) under sub-nanosecond pulse excitation. Finally, a copper-doped CQW film embedded in a vertical cavity surface-emitting laser (VCSEL) structure yields an ultralow lasing threshold of 4.1 mu J cm(-2). Exploiting optical gain from TMDCNMs may help to further boost the performance of colloidal-based lasers.