structures quantum wires and quantum dots
Quantum wells, wires and dots
Ngày tải lên :
14/05/2018, 13:24
... Simple models of quantum wires and dots 8.1 Further confinement 8.2 Schrăodingers equation in quantum wires 8.3 Infinitely deep rectangular wires 8.4 Simple ... electronic and optical properties of semiconductor quantum wells, wires and dots Some background knowledge will be required; we recommend, for example, the books by Ashcroft and Mermin [1] and Blakemore ... r−ωt) (1.6) and therefore −i ∂ ∂ ∂ ˆ i(kx x+ky y+kz z−ωt) ˆı + ˆ + k e = pei(k• r−ωt) ∂x ∂y ∂z Quantum Wells, Wires and Dots: Theoretical and Computational Physics of Semiconductor Nanostructures,...
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Báo cáo " Sol-gel synthesis and particle size characterization of CdSe Quantum dots " ppt
Ngày tải lên :
14/03/2014, 13:20
... long time reaction and its distribution in particle size is in the broadening range In this article, we report on the preparation of CdSe quantum dots (QDs) by sol-gel method and investigate their ... Phuong Thanh, Nguyen Van Hung, Pham Thu Nga, Vu Duc Chinh, Vu Thi Hong Hanh, Synthesis CdSe quantumdots and determine its size from optical spectra, Advances in Optics Photonics Spectroscopy & Applications ... between mean size and specific parameters of QDs [7]: a a E g (a ) = E g + π R B − 1,786R * B − 0,248R * y y a a * y (1) where E g(a) is the effective band gap of QDs with...
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SYNTHESIS OF CDTE AND PBS SEMICONDUCTOR QUANTUM DOTS AND
Ngày tải lên :
28/04/2014, 15:48
... stabilized CdTe quantum dots 14 2.3.1.2 L-Cysteine stabilized CdTe quantum dots 14 2.3.1.3 CA stabilized CdTe quantum dots 14 2.3.2 Synthesis of water soluble CdHgTe quantum dots ... colloidal quantum dots [8-11] for cell labeling [12], cell tracking [13], in vivo imaging [14] and DNA detection [15, 16] Colloidal quantum dots with a wide range of bio- conjugation and with high quantum ... stabilized quantum dots are better suited for biological applications such as in vitro imaging and in vivo sensor Mercury doped CdTe quantum dots, namely alloyed HgxCd1-xTe quantum dots have also...
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Báo cáo toán học: " The structural and optical properties of GaSb/InGaAs type- quantum dots grown on InP (100) substrate" ppt
Ngày tải lên :
20/06/2014, 20:20
... structural and optical properties of type-II GaSb/InGaAs quantum dots [QDs] grown on InP (100) substrate by molecular beam epitaxy Rectangular-shaped GaSb QDs were well developed and no nanodash-like structures ... powers and the fitting curve of the peak energies with the third root of the excitation power Figure Schematic band diagrams (a) Bulk GaSb/InGaAs heterostructures and (b) GaSb/InGaAs QD nanostructures ... quantum- size nanostructures composed of III and V direct-bandgap semiconductor materials, such as GaSb/GaAs [8-10], InAlAs/InP [11], InP/InGaP [12, 13], InP/GaAs [14], GaAsSb/GaAs [15], and InAs/GaSb...
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Báo cáo hóa học: " Effective harvesting, detection, and conversion of IR radiation due to quantum dots with built-in charge" docx
Ngày tải lên :
20/06/2014, 22:20
... two, and three spatial dimensions [13] This simulation tool self-consistently solves Schrödinger, Poisson, and current equations for electrons and holes The conduction and valence bands of the structures ... strain The obtained structures were doped in two different ways: with intra-dot doping (devices B44 and B52) and with inter-dot doping (devices B45 and B53) In devices B44 and B52 (Figure 1a), ... made measurements related to quantum- dot infrared photodetectors JL and VM conducted the design and analysis of all experiments and modeling results All authors read and approved the final manuscript...
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Báo cáo hóa học: " A quantum dots and superparamagnetic nanoparticle-based method for the detection of HPV DNA" ppt
Ngày tải lên :
21/06/2014, 01:20
... cancer marker Her2 and other cellular targets with semiconductor quantum dots Nat Biotechnol 2003, 21:41-46 14 Huo Q: A perspective on bioconjugated nanoparticles and quantum dots Colloids Surf ... excited effectively under ultraviolet band, and their maximum emission peak is about 530 nm, which means the resultant quantum dots is fluorescence-active and could be used as a fluorescent probe ... electrophoresis Characterization of quantum dots Figure The UV absorbance spectrum of QDs The comparison between QDs and superparamagnetic nanoparticle-based hybridization and type-specific PCR was analysized...
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Báo cáo hóa học: " Optical properties of as-grown and annealed InAs quantum dots on InGaAs cross-hatch patterns" doc
Ngày tải lên :
21/06/2014, 01:20
... in a 1-m monochromator and collected by a cooled InGaAs detector using standard lock-in detection technique Results and discussion The optical properties of the as-grown and annealed QDs on CHP ... photoluminescence; QD: quantum dot; QW: quantum well; TD: threading dislocation; WL: wetting layer Acknowledgements S Thainoi and P Changmoang are acknowledged for maintaining the MBE and PL systems ... contributions CH grew and measured the MBE samples, and interpreted the PL spectra SP provided helps, obtained funding, and supervised the group SK conceived, designed, and supervised the experiments;...
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Báo cáo hóa học: " CdTe quantum dots with daunorubicin induce apoptosis of multidrug-resistant human hepatoma HepG2/ADM cells: in vitro and in vivo evaluation" pptx
Ngày tải lên :
21/06/2014, 03:20
... [3] CdTe quantum dots (Cdte QDs) have primarily received attentions in biological and biomedical fields due to their high luminescence efficiency, photostability, and broad absorption and narrow ... Access CdTe quantum dots with daunorubicin induce apoptosis of multidrug-resistant human hepatoma HepG2/ADM cells: in vitro and in vivo evaluation Gen Zhang1, Lixin Shi2, Matthias Selke2 and Xuemei ... nm and emission wavelength at 530 nm The drugs DNR and adriamycin were purchased from Sigma-Aldrich (St Louis, MO, USA) The RPMI 1640 cell culture medium was obtained from Gibco BRL (Grand Island,...
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Báo cáo hóa học: " One-Pot Synthesis of Biocompatible CdSe/CdS Quantum Dots and Their Applications as Fluorescent Biological Labels" doc
Ngày tải lên :
21/06/2014, 08:20
... water-soluble CdSe and CdSe/CdS type-I core–shell QDs with several nanometers in size The one-pot method can provide highquality biocompatible quantum dots without using expensive phosphines and complicated ... the advantages of simpleness, low cost, and green precursor Moreover, the as-received QDs show the tunable and bright PL emission with high quantum yields and high performance as fluorescent biological ... but also the quantum yields of the QDs In our case, the quantum yields of the as-synthesized CdSe cores are around 2–3% In order to passivate their surface trap sites and enhance the quantum yields,...
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báo cáo hóa học:" The structural and optical properties of GaSb/InGaAs type-II quantum dots grown on InP (100) substrate" docx
Ngày tải lên :
21/06/2014, 17:20
... (a) (b) Figure Schematic band diagrams (a) Bulk GaSb/InGaAs heterostructures and (b) GaSb/InGaAs QD nanostructures forming approximately triangular wells electrons and hole characters of type-II ... (type-II) and the GaSb QDs direct interband transition (type-I) respectively, as shown in Figure 4a To explain the PL mechanisms of the type-II GaSb/ InGaAs QD structures, the schematic band diagrams ... STEM measurement SZ, TH, and GH conducted the MBE growth JH, WW, and CH coordinated the study WL provided the idea and conceived the study together with ZL All authors read and approved the final...
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Báo cáo hóa học: " Interaction and Cooperative Nucleation of InAsSbP Quantum Dots and Pits on InAs(100) Substrate" ppt
Ngày tải lên :
22/06/2014, 00:20
... formation of either quantum wires or quantum dots, or even unique island–pit pairs The islands and pits first grow simultaneously as the layer deposition proceeds Both the island height and the pit depth ... cooperative nucleation of the dots pits structures is occurring In particularly, the ‘‘large’’ pits are banded by quantum wires and that the QDs are banded by pits (in the form of ‘‘nano-camomile’’) ... and E energies are approximate and based on FTIR measurements and calculations Finally, note that at the growth of diode heterostructures with the quantum dots and pits inside p–n junction spatial...
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Báo cáo hóa học: " The structural and optical properties of GaSb/InGaAs type-II quantum dots grown on InP (100) substrate" ppt
Ngày tải lên :
22/06/2014, 00:20
... (a) (b) Figure Schematic band diagrams (a) Bulk GaSb/InGaAs heterostructures and (b) GaSb/InGaAs QD nanostructures forming approximately triangular wells electrons and hole characters of type-II ... (type-II) and the GaSb QDs direct interband transition (type-I) respectively, as shown in Figure 4a To explain the PL mechanisms of the type-II GaSb/ InGaAs QD structures, the schematic band diagrams ... STEM measurement SZ, TH, and GH conducted the MBE growth JH, WW, and CH coordinated the study WL provided the idea and conceived the study together with ZL All authors read and approved the final...
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Báo cáo hóa học: " Effects of Shape and Strain Distribution of Quantum Dots on Optical Transition in the Quantum Dot Infrared " doc
Ngày tải lên :
22/06/2014, 01:20
... InAs QD with the height and base ˚ being 80 and 168 A, respectively, and lense-shaped InAs ˚ QD with the height and diameter being 80 and 240 A, respectively The distribution and value of strain ... self-assembled dots: an eight-band study, Phys Rev B 56, 4696 (1997) 16 O Stier, M Grundmann, D Bimberg, Electronic and optical properties of strained quantum dots modeled by 8-band kÁp theory, ... strain eH and the biaxial strain eB are defined as eH rị ẳ exx rị ỵ eyy rị ỵ ezz rị 3ị eB rị ẳ exx rị ỵ eyy rị À 2ezz ðrÞ VHH and VLH are the heavy-hole and light-hole bands, ac, av and b are...
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Báo cáo hóa học: " The Role of Intrinsic and Surface States on the Emission Properties of Colloidal CdSe and CdSe/ZnS Quantum Dots Giovanni Morello Æ Marco Anni Æ Pantaleo Davide Cozzoli " potx
Ngày tải lên :
22/06/2014, 18:20
... states, E1,2 and E2,3 We found E1,2 = 21 meV and E2,3 = 16 meV for core QDs and E1,2 = 21 meV and E2,3 = 13 meV for core/shell QDs The PL time decay for core and core/shell samples (shown in Fig.1B) ... transitions |1i and |2i to carrier recombination from ± 1U and ± 1L states and the transition |3i to a surface states emission By analysing the temperature dependence of the PL intensities I1, I2 and I3 ... the PL of CdSe core and CdSe/ZnS core/shell QDs in the first ns arises from the intrinsic bright ± 1U and ± 1L states with lifetime of about 60 ps and 450 ps, respectively, and from surface states...
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Báo cáo hóa học: " Excitonic Transitions and Off-resonant Optical Limiting in CdS Quantum Dots Stabilized in a Synthetic Glue Matrix" pptx
Ngày tải lên :
22/06/2014, 18:20
... theoretical ratios and experimental ratios agree well if we assign the first four bands observed in PAS to 1se–1sh (band E1), 1pe–1ph (band E2), 1de–1dh (band E3) and 2pe–2ph (band E4) Optical Limiting ... spectroscopy and analyzed in detail using noninteracting particle model We assign the first four bands observed in PAS to 1se–1sh (band E1), 1pe–1ph (band E2), 1de–1dh (band E3) and 2pe–2ph (band E4) ... line shape The analysis yields four peaks at 2.69 eV (denoted as E1 band), 2.81 eV (E2 band), 2.96 eV (E3 band) and 3.21 eV (E4 band) The full width at half maximum (FWHM) of first excitonic transition...
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Báo cáo hóa học: " Electron States and Light Absorption in Strongly Oblate and Strongly Prolate Ellipsoidal Quantum Dots in Presence of Electrical and Magnetic Fields" pot
Ngày tải lên :
22/06/2014, 19:20
... electronic states and direct inter-band light absorption are considered below for strongly oblate ellipsoidal quantum dots (SOEQD) and strongly prolate ellipsoidal quantum dots (SPEQD) at presence ... Darbinyan, and Vice-Rector on R&D Activity, Prof P.S Avetisyan, for administrative and financial support during the research References P Harrison, Quantum Wells, Wires and Dots: Theoretical and Computational ... where v and v0 are sets of quantum numbers (QN) corresponding to the electron and heavy hole, Eg is the forbidden gap width in the bulk semiconductor, X is the incident light frequency and A is...
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Báo cáo hóa học: " Influence of GaAs Substrate Orientation on InAs Quantum Dots: Surface Morphology, Critical Thickness, and Optical Properties" docx
Ngày tải lên :
22/06/2014, 19:20
... further increased to 11.4° and 15.8°, i.e., for samples D and E, as shown by the AFM images in Fig 1g and h there were no QDs found The InAs growth was still 2D growth and QW was formed on each ... Height (nm) (g) 400nm (h) 400nm Fig (a) AFM and (b) histogram of the QD height of sample A; (c) AFM and (d) histogram of the QD height of sample B; (e) AFM and (f) histogram of the QD height of sample ... Results and Discussion Illustrated in Fig are the AFM images and the histograms of QD height Clearly, the surface morphology strongly depended on the substrate orientation As shown by Fig 1a and...
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Báo cáo hóa học: " Whispering gallery modes in photoluminescence and Raman spectra of a spherical microcavity with CdTe quantum dots: anti-Stokes emission and interference effects" ppt
Ngày tải lên :
22/06/2014, 22:20
... so far In conclusion, PL and Raman spectra from a monolayer of CdTe quantum dots were observed due to strong coupling with the spherical microcavity Simultaneous Stokes and anti-Stokes emission ... absorption and a single band edge PL band The blue shift of the QDs absorption band by ~610 meV with respect to bulk CdTe indicates a strong electronic quantum confinement effect Fig Room temperature ... coated by one monolayer of CdTe QDs excited by an Ar+ laser (above band-gap excitation, k = 488 nm, curve 1) and a He–Ne laser (below band-gap excitation, k = 632.8 nm, lower curve 2) The anomalous...
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FINGERPRINTS IN THE OPTICAL AND TRANSPORT PROPERTIES OF QUANTUM DOTS ppt
Ngày tải lên :
26/06/2014, 23:21
... Borodin and Anastas Bukharaev Chapter 13 Quantum Injection Dots 299 Eliade Stefanescu Chapter 14 Quantum Mechanics of Semiconductor Quantum Dots and Rings 333 I Filikhin, S.G Matinyan and B Vlahovic ... GaAs/AlxGa1-xAs Quantum Dot 247 Dong Ho Wu and Bernard R Matis Chapter 12 Tunneling Atomic Force Microscopy of Self-Assembled In(Ga)As/GaAs Quantum Dots and Rings and of GeSi/Si(001) Nanoislands 273 ... Molecules in Self-Organized InP/GaInP Quantum Dots Alexander M Mintairov, James L Merz and Steven A Blundell Chapter InAs Quantum Dots in Symmetric InGaAs/GaAs Quantum Wells 153 Tetyana V Torchynska...
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báo cáo khoa học: " Three-dimensional reconstruction of cell nuclei, internalized quantum dots and sites of lipid peroxidation" docx
Ngày tải lên :
11/08/2014, 00:22
... green channel, corresponding to the quantum dots, and part (d) shows the blue channel, corresponding to the nucleus The nucleus and cell membrane, on the one hand, have relatively simple shapes, ... number of voxels corresponding to quantum dots is 2856; given the pixel size and slice spacing, the volume of one voxel is 0.02 µm3, so the total volume for the quantum dots is 58.8 µm3, or about 5% ... committee and recommended by the ATCC (American Type Culture Collection) Quantum dots were prepared and characterized as described previously [16] Rat pheochromocytoma (PC12 cells) and human...
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