Luminescence of Direct and Indirect Gap Quantum Semiconductor Crystallites

1992 ◽  
Vol 272 ◽  
Author(s):  
L. E. Brus
Keyword(s):  
Quantum Dots ◽  
Size Effect ◽  
Band Gap ◽  
Three Dimensional ◽  
Electronic States ◽  
Quantum Size Effect ◽  
Excited Electronic States ◽  
Quantum Size ◽  
Quantum Semiconductor ◽  
Bulk Band

Semiconductor crystallites (“quantum dots”) small with respect to the bulk exciton Bohr diameter show a three dimensional electronic quantum size effect. Their internal excited electronic states are discrete and shifted to higher energy than the bulk band gap[1,2].

Phenomenological Modeling of Confined Phonon States in TMD Quantum Dots

MRS Advances ◽  
2018 ◽  
Vol 3 (6-7) ◽  
pp. 339-344 ◽  
Author(s):  
Lu Fang ◽  
Tamia Willliam ◽  
Kofi W. Adu ◽  
Mauricio Terrones
Keyword(s):  
Quantum Dots ◽  
Size Effect ◽  
Band Gap ◽  
Bulk Material ◽  
Single Layer ◽  
Interlayer Coupling ◽  
Quantum Size Effect ◽  
Quantum Size ◽  
Indirect Band Gap ◽  
Band Gap Tuning

ABSTRACTSeveral reports have shown band-gap tuning in TMDs, from indirect band gap in the bulk material to a direct gap in single layer due to the absence of interlayer coupling. This unique property stems from the modified electronic states. The phononic properties are extremely modified as well, due to layered effect and quantum size effect. There are several reports on layered effect; however, reports on the confined phonon states in these structures are limited. Thus, we present a preliminary studies of the confined phonon states in TMDs (WS2 and MoS2) quantum dots, and elucidate on the evolution of the phonon lineshape with diameter using a phenomenological model with an envelop function that truncates the phonon wave at the surface of the quantum dot. Furthermore, we delineate the layered effect from the quantum size effect in the phonon lineshape of WS2 and MoS2.

Optimization of Band Structure and Quantum-Size-Effect Tuning for Two-Photon Absorption Enhancement in Quantum Dots

Nano Letters ◽  
2011 ◽  
Vol 11 (3) ◽  
pp. 1227-1231 ◽  
Author(s):  
Lazaro A. Padilha ◽  
Gero Nootz ◽  
Peter D. Olszak ◽  
Scott Webster ◽  
David J. Hagan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Band Structure ◽  
Size Effect ◽  
Quantum Size Effect ◽  
Photon Absorption ◽  
Absorption Enhancement ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Quantum Size

Three-dimensional bandgap-tuned Ag2S quantum dots/reduced graphene oxide composites with enhanced adsorption and photocatalysis under visible light

2018 ◽  
Vol 8 (20) ◽  
pp. 5225-5235 ◽  
Author(s):  
Qian Wu ◽  
Ming Zhou ◽  
Yu Gong ◽  
Qijun Li ◽  
Mingyang Yang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Size Effect ◽  
Visible Light ◽  
Three Dimensional ◽  
Quantum Size ◽  
Reduced Graphene ◽  
Ag2s Quantum Dots ◽  
Enhanced Adsorption ◽  
Oxide Composites

Tuning Ag2S bandgap by quantum size effect and incorporation with rGO to form a three-dimensional composite enhances adsorption and photocatalysis under visible-light.

CdZnSe/Zn(Be)Se Quantum Dot Structures: Size, Chemical Composition and Phonons

2003 ◽  
Vol 799 ◽  
Author(s):  
Y. Gu ◽  
Igor L. Kuskovsky ◽  
J. Fung ◽  
R. Robinson ◽  
I. P. Herman ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Chemical Composition ◽  
Quantum Dot ◽  
Raman Scattering ◽  
Size Effect ◽  
Quantum Size Effect ◽  
Optically Active ◽  
Photoluminescence Excitation ◽  
Quantum Size ◽  
Polarized Raman

ABSTRACTThe size and chemical composition of optically active CdZnSe/ZnSe and CdZnSe/Zn0.97Be0.03Se quantum dots (QDs) are determined using photoluminescence, photoluminescence excitation and polarized Raman scattering spectroscopies. We show that the addition of Be into the barrier enhances the Cd composition and the quantum size effect of optically active QDs. Additionally, surface phonons from QDs are observed in CdZnSe/ZnBeSe nanostructures.

Quantum size effect of CdTe and CdTe/CdS quantum dots

2017 ◽  
Vol 46 (12) ◽  
pp. 1206006
Author(s):  
常存 Chang Cun ◽  
高莹 Gao Ying ◽  
孔德贵 Kong Degui ◽  
张东帅 Zhang Dongshuai ◽  
常青 Chang Qing
Keyword(s):  
Quantum Dots ◽  
Size Effect ◽  
Quantum Size Effect ◽  
Cds Quantum Dots ◽  
Quantum Size

Efficient photocatalytic conversion of benzene to phenol on stabilized subnanometer WO3 quantum dots

2021 ◽  
Vol 11 (19) ◽  
pp. 6537-6542
Author(s):  
Akihide Ohno ◽  
Hiroto Watanabe ◽  
Takahiro Matsui ◽  
Shoichi Somekawa ◽  
Mai Tomisaki ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Mesoporous Silica ◽  
Size Effect ◽  
Quantum Size Effect ◽  
Silica Matrix ◽  
Band Engineering ◽  
Quantum Size

Subnanometer WO3 quantum dots are spontaneously produced in a mesoporous silica matrix. Efficient photocatalytic conversion of benzene to phenol without decomposition of the product is realized by band engineering with a strong quantum size effect.

Quantum size effect and surface defect passivation in size-controlled CsPbBr3 quantum dots

2020 ◽  
Vol 831 ◽  
pp. 154834 ◽  
Author(s):  
Fan Xu ◽  
Xiaobo Kong ◽  
Wenzhi Wang ◽  
Fangying Juan ◽  
Mingxu Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Size Effect ◽  
Surface Defect ◽  
Quantum Size Effect ◽  
Quantum Size ◽  
Defect Passivation ◽  
Size Controlled ◽  
Cspbbr3 Quantum Dots

scholarly journals Luminescence Hole Burning and Quantum Size Effect of Charged Excitons in CuCl Quantum Dots

1996 ◽  
Vol 77 (24) ◽  
pp. 4942-4945 ◽  
Author(s):  
Tadashi Kawazoe ◽  
Yasuaki Masumoto
Keyword(s):  
Quantum Dots ◽  
Size Effect ◽  
Quantum Size Effect ◽  
Hole Burning ◽  
Quantum Size

Fluorescent carbon nano dots from lignite: unveiling the impeccable evidence for quantum confinement

2016 ◽  
Vol 18 (17) ◽  
pp. 12065-12073 ◽  
Author(s):  
Senthil Kumar Thiyagarajan ◽  
Suresh Raghupathy ◽  
Dharmalingam Palanivel ◽  
Kaviyarasan Raji ◽  
Perumal Ramamurthy
Keyword(s):  
Laser Ablation ◽  
Size Effect ◽  
Band Gap ◽  
Quantum Confinement ◽  
Optical Band Gap ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Quantum Size Effect ◽  
Quantum Size ◽  
Fluorescent Carbon

Pulsed laser ablation of lignite in EDA solution exfoliates CDs (CD3) which exhibit the influence of quantum size effect in tuning the optical band gap of CDs.

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