Synthesis and Optical Properties of MoS2 Nanoclusters

1996 ◽  
Vol 452 ◽  
Author(s):  
J. P. Wilcoxon ◽  
P. P. Newcomer ◽  
G. A. Samara
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Quantum Confinement ◽  
Cluster Size ◽  
Surface Recombination ◽  
Spin Orbit ◽  
Photoluminescence Spectra ◽  
Quantum Confinement Effects ◽  
Unit Cells ◽  
Order Of Magnitude

AbstractHighly crystalline nanoclusters of MoS2 were synthesized and their optical absorption and photoluminescence spectra were investigated. Key results include: (1) strong quantum confinement effects with decreasing size; (2) preservation of the quasiparticle (or excitonic) Nature of the optical response for clusters down to ∼2.5 nm in size which are only two unit cells thick; (3) demonstration that 3-D confinement produces energy shifts which are over an order of magnitude larger than those due to 1-D confinement; (4) observation of large increases in the spin-orbit splittings at the top of the valence band at the K and M points of the Brillouin zone with decreasing cluster size; and (5) observation of photoluminescence due to both direct and surface recombination.

Fabrication and Optical Properties of Monodisperse Fine Zinc Oxide Nanorods

2010 ◽  
Vol 663-665 ◽  
pp. 409-412
Author(s):  
Chun Ping Li ◽  
Jian Zhang ◽  
Hua Min Yu ◽  
Xiu Juan Guo
Keyword(s):  
Optical Properties ◽  
Quantum Confinement ◽  
Zno Nanorods ◽  
Optical Quality ◽  
Zinc Oxide Nanorods ◽  
Photoluminescence Spectra ◽  
Aspect Ratios ◽  
Quantum Confinement Effects ◽  
Oxide Nanorods

Highly monodisperse ZnO nanorods were synthesized by simple solution chemical process. The produced ZnO nanorods have uniform diameters about 30 nm with average aspect ratios more than 40. Raman and photoluminescence measurements were used to examine their optical properties. Raman spectrum presents weak quantum confinement effects of the fine nanorods. Laser power-dependent photoluminescence spectra show the products have intense UV emissions with narrow full width at the half maximum (FWHM). All the performed experiments determine the good crystal and optical quality of synthesized nanorods.

QUANTUM CONFINEMENT EFFECTS ON THE OPTICAL PROPERTIES OF ION BEAM SPUTTERED NICKEL OXIDE THIN FILMS

2001 ◽  
Vol 15 (02) ◽  
pp. 191-200 ◽  
Author(s):  
M. GHANASHYAM KRISHNA ◽  
A. K. BHATTACHARYA
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Nickel Oxide ◽  
Band Gap ◽  
Quantum Confinement ◽  
Ion Beam ◽  
Confinement Effects ◽  
Oxide Thin Films ◽  
Quantum Confinement Effects ◽  
Nickel Oxide Thin Films

Quantum confinement effects on the optical properties of ion beam sputtered nickel oxide thin films are reported. Thin films with crystallite sizes in the range 9 to 14 nm have been deposited on to fused silica substrates. There is an increase in band gap, from 3.4 to 3.9 eV, and a decrease in refractive index, from 2.4 to 1.6, with decrease in crystallite size, that can be attributed to quantum confinement effects. The effective mass approximation has been used to explain the observed behaviour in band gap variation.

QUANTUM CONFINEMENT AND COULOMB EFFECTS IN SEMICONDUCTOR QUANTUM DOTS

1990 ◽  
Vol 04 (16) ◽  
pp. 1009-1016 ◽  
Author(s):  
Y.Z. HU ◽  
S.W. KOCH ◽  
D.B. TRAN THOAI
Keyword(s):  
Quantum Dots ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Quantum Confinement ◽  
Semiconductor Quantum Dots ◽  
Optical Absorption Spectra ◽  
Electron Hole ◽  
Quantum Confinement Effects ◽  
Electron Hole Pair ◽  
Coulomb Effects

Coulomb and quantum confinement effects in small semiconductor microcrystallites are analyzed. Energies and wavefunctions for one- and two-electron-hole-pair states are computed and optical absorption spectra are evaluated.

Evaluation of Optical Properties for Nanocrystal Si Dot Layers Fabricated by CVD as a Function of Size Reduction

2012 ◽  
Vol 725 ◽  
pp. 251-254
Author(s):  
Yuki Mizukami ◽  
D. Kosemura ◽  
M. Takei ◽  
Y. Numasawa ◽  
Y. Ohshita ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Optical Properties ◽  
Quantum Confinement ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
X Ray Diffraction ◽  
Confinement Effects ◽  
Quantum Confinement Effects ◽  
Transmission Electron

Raman spectroscopy and photoluminescence were performed in order to understand the optical properties of nanocrystal Si in relation to quantum confinement effects. The nanocrystal Si (nc-Si) dots in the SiO2 layer were fabricated by the H2 plasma treatment and chemical vapour deposition followed by the oxidation of the nc-Si dots surface. The post-annealing was also performed to improve the crystalline quality of nc-Si at 1050 °C for 5 and 10 min. There is a good correlation of the quantum confinement effects between the results of Raman spectroscopy and photoluminescence. The Raman spectra from nc-Si were analysed using the model of Richter et al. As a result, the sizes of the nc-Si dots were consistent with those obtained by transmission electron microscopy and X-ray diffraction. Moreover, the compressive stress in the nc-Si dots were evaluated which was induced by the SiO2 surroundings.

Quantum size effects on the optical properties of nc-Si QDs embedded in an a-SiOx matrix synthesized by spontaneous plasma processing

2015 ◽  
Vol 17 (7) ◽  
pp. 5063-5071 ◽  
Author(s):  
Debajyoti Das ◽  
Arup Samanta
Keyword(s):  
Optical Properties ◽  
Size Effects ◽  
Quantum Confinement ◽  
Plasma Processing ◽  
Blue Shift ◽  
Quantum Size Effects ◽  
Confinement Effects ◽  
Quantum Size ◽  
Quantum Confinement Effects ◽  
Stokes Shifts

An energy blue shift due to quantum confinement effects in tiny nc-Si QDs accompanied by larger Stokes shifts in PL at smaller dimensions.

Growth and Epitaxy of ZnO Nanowires on Brass Substrates

2013 ◽  
Vol 850-851 ◽  
pp. 3-6
Author(s):  
Chao Wang ◽  
Rong Sheng Cai ◽  
Fei Yu Diao ◽  
Lu Yuan ◽  
Guang Wen Zhou ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Confinement ◽  
Nanostructured Material ◽  
Zno Nanowires ◽  
Zno Nanowire ◽  
Epitaxial Relationship ◽  
One Dimensional ◽  
Quantum Confinement Effects ◽  
Low Dimensionality ◽  
One Dimensional Nanostructures

One-dimensional nanostructures exhibit interesting electronic and optical properties due to their low dimensionality leading to quantum confinement effects. ZnO has received lot of attention as a nanostructured material because of unique properties rendering it suitable for various applications. In this paper, ZnO nanowires are synthesized in large quantity through thermal oxidation of brass (Cu0.7Zn0.3alloy). The epitaxial relationship between the brass substrates and ZnO layer and the epitaxial relationship between the ZnO nanowire and ZnO layer have been examined.

Optical properties of thePb2+-based aggregated phase in a CsCl host crystal: Quantum-confinement effects

1995 ◽  
Vol 51 (8) ◽  
pp. 5192-5199 ◽  
Author(s):  
M. Nikl ◽  
K. Nitsch ◽  
K. Polak ◽  
G. P. Pazzi ◽  
P. Fabeni ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Confinement ◽  
Host Crystal ◽  
Confinement Effects ◽  
Quantum Confinement Effects

Tuning Optoelectronic Properties of 4H-SiC QDs Using -H, -OH and -F Surface Functionalisation

2015 ◽  
Vol 821-823 ◽  
pp. 375-378 ◽  
Author(s):  
Marzaini Rashid ◽  
Amit Kumar Tiwari ◽  
Neal Wood ◽  
Patrick Briddon ◽  
Jonathan P. Goss ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Absorption ◽  
Quantum Confinement ◽  
Density Functional ◽  
Size Dependent ◽  
Optical Gap ◽  
Quantum Confinement Effects ◽  
Similar Cluster ◽  
Homo And Lumo ◽  
Surface Functionalisation

Density functional calculations were performed for the –H, –OH and –F functional groups adsorbed onto the surface of pseudo-spherical 4H-SiC quantum dots with diameters ranging from 10 to 22 Å. We find that for the investigated diameter range, the H-terminated SiC-quantum dots exhibit strong size dependent quantum confinement effects, while for –F and –OH terminations, the optical gap remains largely unchanged. The –H termination shows an optical absorption onset well above that of –F and –OH for a similar cluster size, which is attributed to the localisation of HOMO and LUMO states to the quantum dot core. Based on our calculations, we suggest that the –H functionalisation is a more promising route for engineering the optical properties of SiC-quantum dots, since this could lead to a wider control over the optical absorption onsets, when compared to –OH and –F terminations.

Sign in / Sign up

Export Citation Format

Share Document