Optical and Phonon Characterization of Ternary CdSe x S1−x Alloy Quantum Dots

Thi, Le Anh; Cong, Nguyen Dinh; Dang, N. T.; Nghia, Nguyen Xuan; Quang, Vu Xuan

doi:10.1007/s11664-016-4444-2

Cited by 7 publications

(2 citation statements)

References 23 publications

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“…Opposite the InP/ZnSe core/shell QDs, the InP Raman bands shift to lower frequencies after CdSe shelling, and a new Raman band appears with a main feature centered around 208 cm –1 (see Figure f). Closer inspection shows that the latter band consists of a main band at 208.5 cm –1 and a side band at 206 cm –1 , a structure in line with previous reports for CdSe nanocrystals in which both bands where assigned to LO phonons and surface optical phonons of CdSe, respectively. , …”

Section: Resultssupporting

confidence: 90%

Strain Engineering in InP/(Zn,Cd)Se Core/Shell Quantum Dots

et al. 2018

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The formation of core/shell structures has become an established approach to passivate the surface and enhance the photoluminescence quantum yield of semiconductor nanocrystals, quantum dots. However, lattice mismatch between the core and the shell materials results in surface reconstructions at the core/shell interface and compressive or tensile strain in the core and the shell. Concomitantly formed surface traps can have a negative impact on the emission properties. Growing buffer layers with intermediate lattice constants or using alloys to tune the lattice constant is often considered to reduce the reconstruction-induced strain. We present a study that quantitatively relates strain and shell composition in the case of InP/(Zn,Cd)Se core/shell quantum dots. We apply Raman spectroscopy to quantize strain and find that adjusting the composition of the (Zn,Cd)Se shell tunes the strain from compressive to tensile. The transition between both regimes is found at shell compositions where the bulk lattice constants of InP and (Zn,Cd)Se match, which confirms that matching lattice constants is a viable strategy to achieve strain-free core/shell nanocrystals.

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Section: Resultssupporting

confidence: 90%

Strain Engineering in InP/(Zn,Cd)Se Core/Shell Quantum Dots

et al. 2018

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“…II–VI semiconductors are usually direct transition nanocrystals with subtle changes in composition, band gap, particle size, morphology, and other parameters. , The band gap of II–VI alloy semiconductor CdS x Se 1– x (0 < x < 1) can be located between cadmium sulfide (2.45 eV) and cadmium selenide (1.7 eV) by adjusting the composition. , However, CdS x Se 1– x with small size and high surface energy tends to aggregate, and the weakness has an impact on the photoelectrochemical properties of semiconductor nanocrystals. , At the same time, due to the high rate of electron–hole recombination, the low efficiency of photogenerated electron transport severely hampers its application in optoelectronics.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of CdSSe-Decorated Graphene Aerogel with Enhanced Photoelectric Properties

Du,

Lei,

Wang

et al. 2024

ACS Appl. Electron. Mater.

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The folding and conversion of the graphene fragment into honeycomb three-dimensional graphene aerogel (3DrGO) gave it a larger specific surface area and faster carrier mobility. CdS x Se 1−x at a superior S/Se ratio of 0.25:0.75 was loaded on 3DrGO and two-dimensional lamellar graphene (2DrGO) to form CdS 0.25 Se 0.75 /3DrGO and CdS 0.25 Se 0.75 / 2DrGO by the solvothermal method. The effect of the 3DrGO content on the photoelectric performance of CdS 0.25 Se 0.75 /3DrGO was investigated, and the difference between the 2D lamellar structure and 3D porous structure on the photoelectric performance of the composites was compared. As the 3DrGO content rose to 25%, the photocurrent intensity of CdS 0.25 Se 0.75 /3DrGO gradually increased to the maximum of 5.1 × 10 −5 A/m 2 , which was superior to that of CdS 0.25 Se 0.75 /2DrGO at the same 2DrGO content. The results showed that CdS 0.25 Se 0.75 /3DrGO exhibited a higher carrier density (3.79 × 10 20 cm −3 ) and a larger specific surface area (90.58 m 2 /g) and provided a faster transfer channel for photogenerated electrons due to the introduction of 3DrGO.

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