Recently, a new type of inorganic UV absorbers, based on semiconductor nanoparticles, was also used as efficient UV screeners in polymeric systems . The incorporation of semiconductor nanoparticles (NPs) into polymers leads to dramatic changes in optical properties of the polymer . NPs usually have higher photostability than organic molecules and are, therefore, of great interest as additives to polymers. Moreover, it is possible to change the absorp- tion edge of the composite via tuning the particle size.
In the present scenario, enhancing properties of the materials were observed for different applications when nanoparticles were doped. Low cost semiconductor photocatalysts with high photocatalytic efficiency offer great potential for environmental purification and converting photon energy into chemical energy. As a wide band gap(3.37eVat300K)semiconductor with large exciton binding energy(60meV),ZnO is a promising versatile material, which has been intensively studied in the fields of blue–violet light emitting diodes (LEDs), ultraviolet detector, solar cells, field- effect transistors (FETs), sensors, photo catalysts. Though ZnO is photo- catalytically active, its band gap is not wide enough to utilize the high-energy solar radiation. The band gap of ZnO can be controlled via divalent substitution on the cation site. Substituting Mg on Zn site widens the band gap of ZnO, and it is possible to obtain wide band gap Mg-doped ZnO alloys with different ratios of Mg doping, which could be in favor of photocatalytic activities of ZnO under ultraviolet(UV)light irradiation.
morphology optimized for a maximum enhancement. The main approaches towards the preparation of such substrates are colloidal synthesis, use of templates, etching, and self- assembled formation of rough (island-like) metal surfaces . Colloidal metal nanoparticles (NPs) are relatively inexpensive, and a narrow size dispersion of NPs can be obtained, which allows spectrally narrow plasmon peaks to be obtained . While even better homogeneity of the nanostructures and related plasmon characteristics can be achieved by etching and using templates, these kinds of methods are more expensive. Self-assembled growth of island metal films on dielectric or semiconductor substrates can be a good candidate for obtaining SERS substrates with an acceptable ratio of price/quality, provided that the nec- essary homogeneity of the island size is achieved [5, 9–11]. Furthermore, investigations of the SERS effect on various kinds of metal nanostructures and analyte will contribute to the understanding of the role of electromagnetic and chemical contributions to this effect—an issue intensively discussed due to both application importance and funda- mental interest [12, 13].
UV-Visible absorption spectra for bulk CoS and NiS nanoparticles prepared from ZSM-5 zeolite matrices is shown in Figure 3. By comparing the adsorption edge of CoS and NiS bulk with CoSZSM-5 and NiSZSM-5 samples it can be seen that a blue shift in the onset of adsorption is observed in mordenite samples. The phenomenon of blue shift of adsorption edge has been ascribed to a decrease in particle size. It is well known that in case of semiconductors the band gap between the valence and conduction band increases as the size of the particle decreases in the nanosize range. This results in a shift in the adsorption edge to a lower wavelength region. The magnitude of the shift depends on the particle size of the semiconductor. In the present study, the NiSZSM-5 sample showed a blue shift compared to the bulk
semiconducting /electron conducting nature may introduce the partially electronic conductivity in the otherwise pure ionic conducting matrix. Such a composites is termed as mixed ion and electronic conductor (MIEC). The research paper presents some of critical studies of properties of these above mentioned chalcogenide semiconductor embedded in polymer composites. The detailed properties are published elsewhere [17-20]. The motivation behind present work is many fold as under. The various semiconducting particles (PbS, CdS, CuS, Bi 2 S 3 ) differ in
different mass ratios. These two graphs have similar shapes. In application of encryption, it is usually convenient to use the second method. Only two filters, which let the visible light go through at two intervalums around 515 nm and 600 nm are needed. The out come lights could be collected and detected by a simple detector. The ratio of the intensities of the two signals could be calculated by a very simple program, which gives back information about the mass ration of the two semiconductor components. The sizes of the nanoparticles are homogenously small enough to apply in printing or other technique, and hence the products have potential aplicability for encoding purpose.
Metal, semiconductor and metallic alloy NPs are very attractive and interesting area of current research because of their diverse applications in biomedical field. Besides many well known applications of noble metal NPs, many applications of nanoscale semiconductor have been recently studied. It is well known that Si is one of the most important materials for electronic devices. Recently, applications for opto elecronic devices have been examined since efficient visible photoluminescence was observed in Silicon nanocrystallites . Apart from electronic or optical devices, semiconductor nanocrystallites are possible materials for biological applications . Although II-IV semiconductor nanocrystallites such as CdS and CdSe are studied as luminescent markers for biological applications, group V semiconductor nanocrystallites such as Si or Ge have not been studied for biological applications so far. One of the reasons is that the preparation of colloid solutions of silicon is not easy compared with that of II-IV materials. Nanocrystallites embedded in solution are promising for biological applications. The Si-based materials are attractive for biomaterials since they do not include harmful elements such as cadmium or arsenic.
The new class of ionic liquid crystals based on metal alkanoates possesses a number of unique properties, such as intrinsic ionic conductivity, high solvating power, and ability to form time-stable mesomorphic glasses. The me- sophase of metal alkanoates can be used as a nanoreactor for chemical synthesis and stabilization of semiconductor nanoparticles [1-4]. Earlier, electrical conductivity of lyo- tropic and thermotropic ionic liquid crystals of different metal alkanoate was studied . The high electrical con- ductivity was recently observed in the potassium caproate
Optical efficiency of semiconductor nanoparticles (mostly germanium and silicon) having radius below 500nm range, has attractive and complicated spectral nature compare to plasmonic nanoparticles because of displaying together electric and magnetic resonances [7-8] . Although, similarity is both depend on the size, shape of particles and the refractive index of the neighbouring medium. Thus scattering properties of semiconductor nanoparticles can be tuned by use of active mediums (such as liquid crystals).
10 Read more
There are recent studies about phonon transport in semiconductor nanostructures, more specifically analysis of semiconductor crystalline solids confined in the nano- meter range in one, two or three dimensions. They report properties for heat transport of solid particles are of sev- eral orders of magnitude smaller than the corresponding bulk value [21,22,30]. For instance, for very thin silicon films and other nanostructures, the thermal conductivity models have shown that phonon confinement effects could affect thermal conduction by altering phonon spec- tra of the materials . Theoretical studies  have suggested that in the extent Si nanowire diameter be- comes smaller than 20 nm, the phonon dispersion rela- tion could be more easily modified thanks to phonon confinement. In this case, phonon group velocities would be significantly lower than bulk value. Experimental re- ports  have shown that thermal conductivity of sili- con wires of nanometer diameter is two orders of mag- nitude smaller than the bulk value and has strong diame- ter dependence. This suggests that ZnS or InP semicon- ductor particles confined in nanometric scale would also show thermal conductivity (thermal diffusivity) that is significantly lower than that of corresponding bulk value. This is why we make an assumption that when semicon- ductor particles of InP, ZnS or with structure InP@ZnS confined at nanometer scale being dispersed in liquid bases such as toluene with higher thermal diffusivity, the effective thermal diffusivity of formed nanofluid can be significantly decreased. Experimental evidence of nega- tive heat transport enhancement in nanofluids consisting of 2 nm titania semiconductor as nanoparticles dispersed in 50% (w/w) water + ethylene glycol  support this hypothesis. Thus, while metallic and non-metallic nano- particles play an important role in positive increment of thermal diffusivity for liquid bases, the InP, ZnS or InP@ZnS semiconductor nanoparticles confined at nano- metric scale should contribute to decrease the thermal diffusivity. A possible mechanism of heat transport for such semiconductor nanofluids is described in Ref. . This mechanism is related to the nature of heat transport in nanoparticles.
In this work, we investigated the enhancement of photolu- minescence (PL) as a result of exciton–plasmon interactions of semiconductor CdSe/ZnS QDs with an Au NP array on a glass wafer and used the resulting hybrid structures for testing proteins. With the help of optical microscopy, the structure of the Au NPs array surface was studied, depend- ing on the number of the spin coating layers and their baking temperature. The absorption spectra of both the Au NP arrays and their hybrid structures with QDs were recorded and com- pared. The PL spectra of QDs in such hybrid structures were
Cells have been previously visualised in 3-D by electron tomography (Leis et al., 2008) or by examining serial sections (White et al., 1986) on the TEM; however, both of these are accompanied by disadvantages, including limited application to larger volumes, being labour-intensive and time consuming (Denk & Horstmann, 2004, Hughes et al., 2013, Zankel et al., 2009). An alternative, serial block face scanning electron microscopy (SBF SEM), allows the collection of 3-D data through the imaging of a resin block which is serially sectioned inside the chamber of an SEM (Denk & Horstmann, 2004). SBF SEM, which has been used extensively in the biological sciences and is also finding applications in materials sciences (Hashimoto et al., 2013, Hughes et al., 2013, Zankel et al., 2009), is suited to the analysis of the cellular uptake of nanoparticles. An initial report conducted on the uptake of hydroxyapatite nanoparticles by human monocyte-macrophages has provided insight regarding incomplete nanoparticle internalisation, something that was not evident by TEM alone (Motskin et al., 2011).
18 Read more
Abstract. For the traditional cold and hot compress products, it is not easy to carry, the cooling and heating speed is slow and the temperature is uncontrollable. This paper proposes a safe, pollution-free, portable cold and hot therapy device. We can view and adjust temperature by using semiconductor refrigeration chip, temperature controller, wireless Bluetooth, controller, cooling fan and other modules. With this technology, cold and hot compress function can be switched easily. Putting medicine bag with traditional Chinese herb on the device is beneficial to improve blood circulation and body immunity. It can be also promote the absorption of inflammatory exudation and edema. Putting water bag on it, the metabolism of blood seepage, blood stasis and hematoma can be reduced.
I would like to thank staff of Semiconductor and Microsystems Fabrication Laboratory specially Patricia Meller and Sean O’Brien for constant help while working in laboratory. I would like to thank Scott Blondell, John Nash, Bruce Tolleson, Rich Battaglia and Dave Yackoff for training and certifying on Varian 350D Implanter; ASML stepper, P5000, CVC evaporator, LAM 4600; LPCVD, DryTek Quad, SSI track; LAM 490, Implanter; wet chemical benches, RTA tool and Bruce furnace respectively.
124 Read more
built superlattices described in previous section, we are interested in the heat transfer phenomena related to the metal/semiconductor interfaces. The prediction of heat transfer in these systems becomes challenging when the thickness of the layers reaches the same order of magni- tude as the PMFP. For heat transfer studies, MD is well suited for dielectrics since only phonons carry heat. For metals, coupling between phonons and electrons can be modelled with the two-temperature model . For the above systems, it has been proven that the Kapitza resis- tance is mainly due to phonon energy transmission through the interfaces [23,24]. The interfacial thermal resistance, known as the Kapitza resistance [25,26] is important to be studied as it might become of the same order of magnitude than the film thermal resistance. In this section, interatomic potentials for Ag and Si are dis- cussed. Using NEMD simulations, for an average tem- perature of 300 K, the Kapitza resistance of Si/Ag systems is determined.
10 Read more
The staff of the Semiconductor & Microsystems Fabrication Laboratory at RIT is thanked for their technical expertise and assistance in keeping all of the tools used for this work up and running. Specifically, I would like to thank Bruce Tolleson, whom spent countless hours helping me bring up the Westech 372 wafer polisher for CMP, continuous support on the DryTek Quad RIE and LPCVD system. You are the best technician we have and it’s been a pleasure working with you. I would also like to thank David Yackoff for his help with the Canon Stepper and spending 3 days straight helping to calibrate the two Rapid Thermal Processors which are now running the best they have ever run. Additionally I thank: Sean O’Brien, Scott Blondell, Tom Grimsley, Rich Battaglia and John Nash.
159 Read more
The 807nm pump band of erbium-doped amplifiers almost coincides with the wavelength that is of particular interest for semiconductor laser pumping of Nd:YAG microlasersl^^. These microlasers have received a lot of attention recently because of the significant advances that have been made in the manufacture of high-power GaAlAs sem iconductor lasers^^^. Thus semiconductor pump lasers having CW output powers up to IW are readily available and can thus be directly used for the excitation of erbium-doped fibre devices. Only one significant difference exists between a pump source for microlasers and fibre amplifiers which is that the output must be able to be efficiently coupled into the single-mode optical fibre of the erbium amplifier. Consequently, the higher power, multiple-stripe arrays (up to IW) are unattractive, giving only -5% coupling efficiency to lensed single-mode fibres. However, studies into injection locking and self-injection locking of high power arrays has enabled -40% coupling efficiency to single-mode optical fibres to be demonstrated!^'* because of their improved spatial beam quality. Also it has been shown that the good beam quality obtained from broad (3-5|xm) single-stripe lasers can allow >40% pump coupling efficiency!^^. Although the total output power is relatively modest (-200mW) for broad-stripe devices^^^, a factor of four increase in total coupled power can be achieved over an array with an output power of 0.5W.
214 Read more
Metal-Semiconductor-Metal is one of the photodetectors that uses in optical detection. The characteristic of these detectors is improved by Plasmonic Science. Some of these characteristics include higher sensitivity, greater efficiency and improved optical absorption coefficient. In these structures, the detection parameters were optimized by using metal diffraction mesh and nanoparticles. Also making the very small detectors becomes much easier by Plasmonic Science, which leads to the Optical Integrated circuits. Today, Plasmonic has wide applications in various fields of optical and electronic devices. Here some examples of the work done in the field of application of Plasmonic photodetectors will be discussed. In 2004, it was shown that by placing a Nano layer of light-absorbing semiconductor between two electrodes with a small gap, we can have a MSM detectector with more than 50% efficiency and cutoff of frequency of more than 300 GHz . In this structure, Nano semiconductors string was used between metal strings which have lower cross-section area than λ/8. Results show that 75% efficiency and cutoff frequency of 500 GHz can be obtained theoretically. This structure was built for 800nm wavelength.
were 5.9 nm and 6.7 nm, respectively (Figure 2C and D). The phase transfer did not signi ﬁ cantly alter the particle size or particle size distribution (Figure S2), but provided an addi- tional degree of freedom in particles functionalization. The electrostatic approach used to fabricate the hybrid NPs was based on interactions between oppositely charged assembly components (Figure S1A). For example, as PEI is one of the most successful and widely studied transfection and gene delivery cationic polymers, it was used for encapsulating the semiconductor QDs onto SPIO-DX NPs. During assembly, particle characteristic tracking was done by measurement of the HD (Figure 3A) and zeta potential at different stages of fabrication (Figure 4). As determined by zeta potential
The in-vitro antimicrobial activity of Nickel oxide Nanoparticles was evaluated against the gram-positive Staphylococcus aureus (MTCC-7443) and gram-negative Escherichia coli (MTCC-40) by disc diffusion method in Mueller Hinton Agar Plate [27-31]. 100 µL of the pathogenic bacteria cultures were transferred onto plate for 24 hours cultures of test microorganisms in broth were used for the seeding and poured to the Petri plates and allowed to cool to room temperature, in laminar air flow. Nickel oxide Nanoparticles were loaded into 6mm sterile discs and placed on the culture plates and incubated at 37 0 C for 24 hours. The comparative stability of discs containing Gentamycin was made. By measuring the diameter of the ZOI formed around the disc, the antibacterial activity of Nickel oxide Nanoparticles was determined. The diameters of the zone of inhibitions (in mm) were measured after completion of the incubation. The antimicrobial activity of Nickel oxide Nanoparticles was investigated by zone of inhibition by Kirby-Bauer disc diffusion method. Disposable plates inoculated with the Gram-positive and Gram-negative bacteria, such as Staphylococcus aureus and Escherichia coli