InAs nanocrystals

Guzellan A A et al 1997 Colloidal chemical synthesis and characterization of InAs nanocrystal quantum dots Appl. Phys. Lett. 69 1432... 

Katz D, Millo O, Kan S, Banin U (2001) Control of charging in resonant tunneling through InAs nanocrystal quantum dots. Appl Phys Lett 79 117-119... 

Nanocrystalline InAs is obtained by the reaction of (Me3Si)3As with InCb or by reaction of hiCls with NasAs, respectively. A solvothermal ronte has been proposed to prepare InAs nanocrystals, which involves co-rednction of InCb and AsCb by Zn. The high qnality nanocrystalhne InAs can be obtained by the thermolysis of a mixture of InCb and As(NMe2)3 In addition, InSb nanocrystals can also be obtained by the solvothermal reduction route. ... 

Banin U., Lee J. C., GnzeUan A. A., Kadavanich A. V., Alivisatos A. P., Jaskolski W., Bryant G., Efros A. L. and Rosen M. (1998), Size-dependent electronic level structure of InAs nanocrystal quantum dots test of multiband effective mass theory , J. Chem. Phys. 109, 2306-2309. 

Figure 15.25 (a) Size- and material-dependent emission spectra of several snrfactant-coated semiconductor nanocrystals (quantnm dots) in a variety of sizes. The blue series (right) represents different sizes of CdSe nanocrystals with diameters of 2.1, 2.4, 3.1, 3.6 and 4.6 nm (from right to left). The green series (centre) is of InP nanocrystals with diameters of 3.0, 3.5 and 4.6 nm. The red series (left) is of InAs nanocrystals with diameters of 2.8, 3.6, 4.6, and 6.0 nm. (b) A true-colour image of the fluorescence of a series of silica-coated core (CdSe)-shell (ZnS or CdS) nanocrystals (reproduced from [39] with permission from AAAS). See plate section for colour version of this image. 

This section first provides a general discussion of the synthetic strategy employed for group III-V semiconductor nanocrystals, followed by a description of the synthesis of InAs nanocrystals as a prototypical example. The characterization of the particles produced, using a variety of methods, is briefly reviewed, after which details are provided of the synthesis of core-shell nanocrystals with III-V semiconductor cores, focusing particularly on InAs cores. 

Figure 3.22 Powder X-ray diffraction spectra of InAs nanocrystals with different sizes. The domain size was calculated from the width of the reflections, as detailed in the text. Reproduced from Ref [188].

The powder XRD analysis of a series of InAs nanocrystal sizes is shown in Figure 3.22, where the peak positions are seen to index well with the bulk InAs lattice reflections. Information on the domain size of the sample can be obtained from the width of the lattice reflections, using the Debye-Scherrer formula for spherical particles [52] ... 

Quantum confinement effects of nanocrystals are evidenced most clearly in the optical properties of the system, as the electronic energy levels of the clusters become a function of size (a detailed account of this aspect is provided in Chapter 5). The basic optical characterization of semiconductor nanocrystals provides important information on particle size - from the position of the band gap energy, and the size distribution - from the sharpness of peaks in absorption and luminescence. Figure 3.25 shows the room-temperature absorption spectra for a series of InAs nanocrystal sizes, along with the photoluminescence spectra. The quantum confinement effects are clearly evident from the size-dependent nature of the spectra, with the band gap in all samples being shifted substantially from the bulk InAs gap of 0.42 eV. In all samples, the absorption onset is characterized by a distinct feature at... 

Figure 5.1 (a) Optical spectroscopy of InAs nanocrystals, with mean radius of 2.5 nm. The top frame shows the absorption (solid line), and the photoluminescence (dotted line) for the sample. The lower frame shows a size-selected photoluminescence excitation (PLE) spectrum, where eight transitions are resolved, measured... 

Figure 5.2 STM measurements on single InAs nanocrystal 3.2 nm in radius, acquired at 4.2 K. The QDs are linked to the gold substrate by dithiol (DT) molecules, as shown schematically in the right inset. The left inset presents a 10 X 10 nm STM topographic image of the QD. The tunneling I-V characteristic is presented in...

Fig. 4.7. Size evolution of the tunneling dl/dV vs. V characteristics of InAs nanocrystals acquired at 4.2 K. The spectra are displaced vertically for clarity. Representative nanocrystal radii are denoted (reproduced with permission from [674])...

Figures. STM of InAs Nanocrystals deposited on Pt substrate. Fane/A- top view.

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