SwePub - sökning: WFRF:(Willander M.)

Numrering	Referens	Omslagsbild	Hitta
1.	Imran, Z, et al. (författare) Fabrication of cadmium titanate nanofibers via electrospinning technique 2012 Ingår i: Ceramics International. - : Elsevier. - 0272-8842 .- 1873-3956. ; 38:4, s. 3361-3365 Tidskriftsartikel (refereegranskat)abstract Here we present an electrospinning technique for the fabrication of cadmium titanate/polyvinyl-pyrrolidone composite nanofibers. The composite nanofibers are then annealed at 600 degrees C to obtain ilmenite rhombohedral phase cadmium titanate nanofibers. The structure, composition, thermal stability and optical properties of as synthesized and annealed cadmium titanate nanofibers are characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy. The average diameter and length of the nanofibers are found to be similar to 150-200 nm and similar to 100 mu m, respectively.
2.	Batool, S S., et al. (författare) Comparative Analysis of Ti, Ni, and Au Electrodes on Characteristics of TiO2 Nanofibers for Humidity Sensor Application 2013 Ingår i: Journal of Materials Science & Technology. - : Elsevier. - 1005-0302. ; 29:5, s. 411-414 Tidskriftsartikel (refereegranskat)abstract The effect of metal (Ti, Ni, and Au) electrodes on humidity sensing properties of electrospun TiO2 nanofibers was investigated in this work. The devices were fabricated by evaporating metal contacts on SiO2 layer thermally grown on silicon substrate. The separation between the electrodes was 90 mm for all sensors. The sensors were tested from 40% to 90% relative humidity (RH) by AC electrical characterization at room temperature. When sensors are switched between 40% and 90% RH, the corresponding response and recovery time are 3 s and 5 s for Ti-electrode sensor, 4 s and 7 s for Ni-electrode sensor, and 7 s and 13 s for Au-electrode sensor. The hysteresis was 3%, 5% and 15% for Ti-, Ni-, and Au-electrode sensor, respectively. The sensitivity of Ti, Ni, and Au-electrode sensors are 7.53 M Omega/% RH, 5.29 MU/% RH and 4.01 M Omega/% RH respectively at 100 Hz. Therefore Ti-electrode sensor is found to have linear response, fast response and recovery time and higher sensitivity as compared with those of Ni- and Au-electrode sensors. Comparison of humidity sensing properties of sensors with different electrode material may propose a compelling route for designing and optimizing humidity sensors.
3.	Batool, S S, et al. (författare) Silica nanofibers based impedance type humidity detector prepared on glass substrate 2013 Ingår i: Vacuum. - : Elsevier. - 0042-207X .- 1879-2715. ; 87, s. 1-6 Tidskriftsartikel (refereegranskat)abstract Impedance type relative humidity detector is fabricated by depositing electrospun silica nanofibers on glass substrate. The silica nanofibers with an average diameter similar to 150 nm and length similar to 100 mu m were used. Thermogravimetric and differential scanning calorimetric analysis confirm that the accurate annealing temperature is 500 degrees C for complete removal of PVP. Humidity detecting devices were fabricated by defining titanium electrodes on top of the silica nanofibers. The performance of silica nanofibers humidity detectors was tested by AC electrical measurements at 40-90% relative humidity. The response and the recovery times were 5 s and 3 s, respectively, between 40% and 90% relative humidity. Contribution of dipoles, space charge polarization, relaxation of these dipoles and low frequency dispersion phenomenon were observed during impedance measurements.
4.	Fakhar-e-Alam, M, et al. (författare) Role of ALA sensitivity in HepG2 cell in the presence of diode laser 2011 Ingår i: LASER PHYSICS. - : Springer Science Business Media. - 1054-660X. ; 21:5, s. 972-980 Tidskriftsartikel (refereegranskat)abstract 5-aminolevulinic acid (ALA) being an amazing second generation photosensitizer was studied as photodamaging drug on hepatocellular carcinoma (HepG2) cells. The mentioned photosensitizer is converted to PpIX in HepG2 cells in vitro, inducing haem in the cell causing generation of singlet oxygen leading to cell apoptosis. Cell uptake of 5-ALA was evaluated with different concentrations (ranging from 0-800 mu g/ml) for 0-49 h incubation period. ALA administered in HepG2 cells is converted into Protoporphyrin IX (PpIX) which has a short half life and constitute a good hematoporphyrin derivative (HPD). Cytotoxicity of ALA in dark and cellular viability without ALA in the presence of light was studied, showing minimal toxic effects in dark with no photodamaging effect on mentioned cells in absence of ALA were observed. The optimal uptake of photosensitizer (5-ALA) in HepG2 cells was investigated by means of spectrophotometeric measurements, cellular viability was determined by means of neutral red assay (NRA). It was observed that with different concentrations (0-800 mu g/ml) of ALA or light doses (0-160 J/cm(2)), there were no significant effect on cellular viability when studied independently. The novel of photocytotoxic study indicates that light dose of 120 J/cm(2) produces convincing Photodynamic therapy (PDT) results for HepG2 cells incubated with 262 mu g/ml of 5-ALA deducting that HepG2 cell line is sensitive to ALA mediated PDT. Finally morphological changes in HePG2 cells were determined before and after ALA-mediated PDT by confocal microscopy.
5.	Imran, Z., et al. (författare) Excellent humidity sensing properties of cadmium titanate nanofibers 2013 Ingår i: Ceramics International. - : Elsevier. - 0272-8842 .- 1873-3956. ; 39:1, s. 457-462 Tidskriftsartikel (refereegranskat)abstract We report humidity sensing characteristics of CdTiO3 nanofibers prepared by electrospinning. The nanofibers were porous having an average diameter and length of similar to 50-200 nm and similar to 100 mu m, respectively. The nanofiber humidity sensor was fabricated by defining aluminum electrodes using photolithography on top of the nanofibers deposited on glass substrate. The performance of the CdTiO3 nanofiber humidity sensor was evaluated by AC electrical characterization from 40% to 90% relative humidity at 25 degrees C. The frequency of the AC signal was varied from 10(-1) to 10(6) Hz. Fast response time and recovery time of 4 s and 6 s were observed, respectively. The sensor was highly sensitive and exhibited a reversible response with small hysteresis of less than 7%. Long term stability of the sensor was confirmed during 30 day test. The excellent sensing characteristics prove that the CdTiO3 nanofibers are potential candidate for use in high performance humidity sensors.
6.	Kashif, M., et al. (författare) Effect of Different Seed Solutions on the Morphology and Electrooptical Properties of ZnO Nanorods 2012 Ingår i: Journal of Nanomaterials. - : Hindawi Publishing Corporation. - 1687-4110 .- 1687-4129. ; 2012:452407 Tidskriftsartikel (refereegranskat)abstract The morphology and electrooptical properties of ZnO nanorods synthesized on monoethanolamine-based seed layer and KOH-based seed layer were compared. The seed solutions were prepared in monoethanolamine in 2-methoxyethanol and potassium hydroxide in methanol, respectively. Zinc acetate dihydrate was as a common precursor in both solutions. The nanorod-ZnOs were synthesized via the spin coating of two different seed solutions on silicon substrates followed by their hydrothermal growth. The scanning electron microscopy (SEM), X-ray diffraction (XRD), photoluminescence (PL), and Raman studies revealed that the ZnO nanorods obtained from monoethanolamine-based seed layer had fewer defects, better crystals, and better alignment than those realized via KOH-based seed layer. However, the current-voltage (I-V) characteristics demonstrated better conductivity of the ZnO nanorods obtained via KOH-based seed layer. The current measured in forward bias was 4 mA and 40 mu A for ZnO-nanorods grown on KOH-based seed layer and monoethanolamine-based with the turn on voltage of approximately 1.5 V and 2.5V, respectively, showing the feasibility of using both structures in optoelectric devices.
7.	Batool, S S., et al. (författare) Investigation of dielectric relaxation behavior of electrospun titanium dioxide nanofibers using temperature dependent impedance spectroscopy 2013 Ingår i: Ceramics International. - : Elsevier. - 0272-8842 .- 1873-3956. ; 39:2, s. 1775-1783 Tidskriftsartikel (refereegranskat)abstract The electrospinning method has been utilized in the fabrication of titanium dioxide nanofibers (TNFs) with an average diameter of similar to 50 nm and length of 100 um. Effect of temperature on the dielectric relaxation behavior of the fabricated nanofibers have been studied using AC impedance spectroscopy. The morphological, structural and compositional aspects as well as the optical properties of the TNFs have been investigated by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive x-ray spectroscopy (EDX) and ultraviolet visible (UV vis) absorption spectrum. The permittivity behavior of the device at the frequency below 10(2) Hz shows the relaxation contribution along with the electrode polarization. Dielectric loss peak in loss tangent also confirms the presence of relaxing dipoles in TNFs. The AC conductance as a function of frequency confirms the semiconducting nature of TNFs and obeys Jonschers power law except a small deviation in the low frequency region. DC conductivity increases with increase in temperature.
8.	Bruce, SPO, et al. (författare) Design and realization of a millimeter-wave Si/SiGe HBT frequency multiplier 1998 Ingår i: IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9480. ; 46:5, s. 695-700 Tidskriftsartikel (refereegranskat)abstract In this paper, the design of an active millimeterwave frequency doubler using an Si/SiGe heterojunction bipolar transistor (HBT) as the active device is studied. Simulations are made using a developed physics-based large-signal model for Si/SiGe HBT's, wh
9.	Fakhar-E-Alam, Muhammad, et al. (författare) RETRACTED: Empirical Modeling of Physiochemical Immune Response of Multilayer Zinc Oxide Nanomaterials under UV Exposure to Melanoma and Foreskin Fibroblasts 2017 Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 7 Tidskriftsartikel (refereegranskat)abstract Carcinogenesis is a complex molecular process starting with genetic and epigenetic alterations, mutation stimulation, and DNA modification, which leads to proteomic adaptation ending with an uncontrolled proliferation mechanism. The current research focused on the empirical modelling of the physiological response of human melanoma cells (FM55P) and human foreskin fibroblasts cells (AG01518) to the multilayer zinc oxide (ZnO) nanomaterials under UV-A exposure. To validate this experimental scheme, multilayer ZnO nanomaterials were grown on a femtotip silver capillary and conjugated with protoporphyrin IX (PpIX). Furthermore, PpIX-conjugated ZnO nanomaterials grown on the probe were inserted into human melanoma (FM55P) and foreskin fibroblasts cells (AG01518) under UV-A light exposure. Interestingly, significant cell necrosis was observed because of a loss in mitochondrial membrane potential just after insertion of the femtotip tool. Intense reactive oxygen species (ROS) fluorescence was observed after exposure to the ZnO NWs conjugated with PpIX femtotip model under UV exposure. Results were verified by applying several experimental techniques, e.g., ROS detection, MTT assay, and fluorescence spectroscopy. The present work reports experimental modelling of cell necrosis in normal human skin as well as a cancerous tissue. These obtained results pave the way for a more rational strategy for biomedical and clinical applications.
10.	Fakhar-e-Alam, M., et al. (författare) Tumoricidal Effects of Nanomaterials in HeLa Cell Line 2011 Ingår i: Laser physics. - : MAIK Nauka/Interperiodica. - 1054-660X .- 1555-6611. ; 21:11, s. 1978-1988 Tidskriftsartikel (refereegranskat)abstract The current study exhibits the cellular response of HeLa (cervical cancer) cells to metal oxides ultrafine nanomaterials e.g. manganese dioxide nanowires (MnO(2) NRs), iron oxide nanoparticles (Fe(2)O(3) NPs) and zinc oxide nanorods (ZnO NRs) as bare and as conjugated with photosensitizers. For cytotoxic evaluations, the cellular morphology, (MTT) assay, reactive oxygen species (ROS) production were used for cases with and without photo sensitizer as well illuminated with UV-visible laser exposed conditions. Three different photosensitizers were tested. These are 5-aminolevulinic acid (5-ALA), Photofrin (R), and protoporphyrin dimethyl ester (PPDME). Significant loss in cell viability was noted with 100-500 mu g/ml in bare and conjugated forms of the metal oxides used. The effect was insignificant with lower concentrations (0.05-50 mu g/ml). While notable anticancer effect of 5-ALA under 30 J/cm(2) of diode laser irradiation was noted as compared to other photo sensitizer. By increasing the UV irradiation time of labeled cells, generation of ROS was observed, indicating the possibility of achieving efficient photodynamic therapy (PDT).
11.	Jamil, Hira, et al. (författare) Electrospun titanium dioxide nanofiber humidity sensors with high sensitivity 2012 Ingår i: Ceramics International. - : Elsevier. - 0272-8842 .- 1873-3956. ; 38:3, s. 2437-2441 Tidskriftsartikel (refereegranskat)abstract Titanium dioxide nanofibers were synthesized using electrospinning technique. The nanofibers were porous with an average diameter and length of similar to 150 nm and 200 p,m, respectively. Humidity-sensing devices were fabricated by lithographically defined aluminum electrodes on top of the nanofibers deposited on silicon dioxide grown thermally on a silicon substrate. The performance of a TiO2 nanofiber humidity sensor was tested by AC and DC electrical measurements at 40-90% relative humidity. The response and the recovery time were 1 s and 4 s, respectively, between 40% and 90% relative humidity. The sensitivity of the TiO2 humidity sensor in the range of 40-90% RH was 150 M Omega/%RH and 20 M Omega/%RH at 10 Hz and 100 Hz, respectively. The excellent sensing characteristics are attributed to the porous nature and the small diameter of the nanofibers.
12.	Usman Ali, Syed M., et al. (författare) Functionalised zinc oxide nanotube arrays as electrochemical sensors for the selective determination of glucose 2011 Ingår i: Micro & Nano Letters. - : Institution of Engineering and Technology (IET). - 1750-0443. ; 6:8, s. 609-613 Tidskriftsartikel (refereegranskat)abstract In the present study, highly oriented single-crystal zinc oxide nanotube (ZnO-NT) arrays were prepared by a trimming of ZnO nanorods along the c-axis on the gold-coated glass substrate having a diameter of 100-200 nm and a length of similar to 1 mu m using a low-temperature aqueous chemical growth process. The prepared (ZnO-NT) arrays were further used as electrochemical enzyme-based glucose sensors through immobilisation of glucose oxidase by the physical adsorption method in conjunction with a Nafion coating. The electrochemical response of the sensor was found to be linear over a relatively wide logarithmic concentration range from 0.5 x 10(-6) to 12 x 10(-3) M. The proposed sensor showed a high sensitivity of 69.12 mV/decade with R = 0.9934 for sensing of glucose. A fast-response time less than 4 s with good selectivity, reproducibility and negligible response to common interferents such as ascorbic acid and uric acid prevailed.
13.	Willander, Magnus, et al. (författare) Zinc oxide nanorod based photonic devices : recent progress in growth, light emitting diodes and lasers 2009 Ingår i: NANOTECHNOLOGY. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 20:33, s. 332001- Forskningsöversikt (refereegranskat)abstract Zinc oxide (ZnO), with its excellent luminescent properties and the ease of growth of its nanostructures, holds promise for the development of photonic devices. The recent advances in growth of ZnO nanorods are discussed. Results from both low temperature and high temperature growth approaches are presented. The techniques which are presented include metal-organic chemical vapour deposition (MOCVD), vapour phase epitaxy (VPE), pulse laser deposition (PLD), vapour-liquid-solid (VLS), aqueous chemical growth (ACG) and finally the electrodeposition technique as an example of a selective growth approach. Results from structural as well as optical properties of a variety of ZnO nanorods are shown and analysed using different techniques, including high resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), photoluminescence (PL) and cathodoluminescence (CL), for both room temperature and for low temperature performance. These results indicate that the grown ZnO nanorods possess reproducible and interesting optical properties. Results on obtaining p-type doping in ZnO micro- and nanorods are also demonstrated using PLD. Three independent indications were found for p-type conducting, phosphorus-doped ZnO nanorods: first, acceptor-related CL peaks, second, opposite transfer characteristics of back-gate field effect transistors using undoped and phosphorus doped wire channels, and finally, rectifying I-V characteristics of ZnO: P nanowire/ZnO:Ga p-n junctions. Then light emitting diodes (LEDs) based on n-ZnO nanorods combined with different technologies (hybrid technologies) are suggested and the recent electrical, as well as electro-optical, characteristics of these LEDs are shown and discussed. The hybrid LEDs reviewed and discussed here are mainly presented for two groups: those based on n-ZnO nanorods and p-type crystalline substrates, and those based on n-ZnO nanorods and p-type amorphous substrates. Promising electroluminescence characteristics aimed at the development of white LEDs are demonstrated. Although some of the presented LEDs show visible emission for applied biases in excess of 10 V, optimized structures are expected to provide the same emission at much lower voltage. Finally, lasing from ZnO nanorods is briefly reviewed. An example of a recent whispering gallery mode (WGM) lasing from ZnO is demonstrated as a way to enhance the stimulated emission from small size structures.
14.	Ali, A., et al. (författare) Cobalt oxide magnetic nanoparticles-chitosan nanocomposite based electrochemical urea biosensor 2015 Ingår i: Indian Journal of Physics. - : Springer Verlag (Germany). - 0973-1458 .- 0974-9845. ; 89:4, s. 331-336 Tidskriftsartikel (refereegranskat)abstract In this study, a potentiometric urea biosensor has been fabricated on glass filter paper through the immobilization of urease enzyme onto chitosan/cobalt oxide (CS/Co3O4) nanocomposite. A copper wire with diameter of 500 mu m is attached with nanoparticles to extract the voltage output signal. The shape and dimensions of Co3O4 magnetic nanoparticles are investigated by scanning electron microscopy and the average diameter is approximately 80-100 nm. Structural quality of Co3O4 nanoparticles is confirmed from X-ray powder diffraction measurements, while the Raman spectroscopy has been used to understand the chemical bonding between different atoms. The magnetic measurement has confirmed that Co3O4 nanoparticles show ferromagnetic behavior, which could be attributed to the uncompensated surface spins and/or finite size effects. The ferromagnetic order of Co3O4 nanoparticles is raised with increasing the decomposition temperature. A physical adsorption method is adopted to immobilize the surface of CS/Co3O4 nanocomposite. Potentiometric sensitivity curve has been measured over the concentration range between 1 x 10(-4) and 8 x 10(-2) M of urea electrolyte solution revealing that the fabricated biosensor holds good sensing ability with a linear slope curve of similar to 45 mV/decade. In addition, the presented biosensor shows good reusability, selectivity, reproducibility and resistance against interferers along with the stable output response of similar to 12 s.
15.	Ali, A., et al. (författare) Potentiometric urea biosensor utilizing nanobiocomposite of chitosan-iron oxide magnetic nanoparticles 2013 Ingår i: 21st International Laser Physics Workshop 23–27 July 2012, Calgary, Canada. - : Institute of Physics (IOP). Konferensbidrag (refereegranskat)abstract The iron oxide (Fe3O4) magnetic nanoparticles have been fabricated through a simple, cheap and reproducible approach. Scanning electron microscope, x-rays powder diffraction of the fabricated nanoparticles. Furthermore, the fabrication of potentiometric urea biosensor is carried out through drop casting the initially prepared isopropanol and chitosan solution, containing Fe3O4 nanoparticles, on the glass fiber filter with a diameter of 2 cm and a copper wire (of thickness −500 μm) has been utilized to extract the voltage signal from the functionalized nanoparticles. The functionalization of surface of the Fe3O4 nanoparticles is obtained by the electrostatically immobilization of urease onto the nanobiocomposite of the chitosan- Fe3O4 in order to enhance the sensitivity, specificity, stability and reusability of urea biosensor. Electrochemical detection procedure has been adopted to measure the potentiometric response over the wide logarithmic concentration range of the 0.1 mM to 80 mM. The Fe3O4 nanoparticles based urea biosensor depicts good sensitivity with ~42 mV per decade at room temperature. Durability of the biosensor could be considerably enhanced by applying a thin layer of the nafion. In addition, the reasonably stable output response of the biosensor has been found to be around 12 sec.
16.	AlSalhi, M S., et al. (författare) Growth and characterization of ZnO nanowires for optical applications 2013 Ingår i: Laser physics. - : Institute of Physics Publishing (IOPP). - 1054-660X .- 1555-6611. ; 23:6 Tidskriftsartikel (refereegranskat)abstract In the present work, cerium oxide CeO2 nanoparticles were synthesized by the sol-gel method and used for the growth of ZnO nanorods. The synthesized nanoparticles were studied by x-ray diffraction (XRD) and Raman spectroscopic techniques. Furthermore, these nanoparticles were used as the seed layer for the growth of ZnO nanorods by following the hydrothermal growth method. The structural study of ZnO nanorods was carried out by means of field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and XRD techniques. This study demonstrated that the grown ZnO nanorods are well aligned, uniform, of good crystal quality and have diameters of less than 200 nm. Energy dispersive x-ray (EDX) analysis revealed that the ZnO nanorods are composed only of zinc, cerium as the seed atom, and oxygen atoms, with no other impurities in the grown nanorods. Moreover, a photoluminescence (PL) approach was applied for the optical characterization, and it was observed that the near-band-edge (NBE) emission was the same as that of the zinc acetate seed layer, however the green and orange/red emission peaks were slightly raised due to possibly higher levels of defects in the cerium oxide seeded ZnO nanorods. This study provides an alternative approach for the controlled synthesis of ZnO nanorods using cerium oxide nanoparticles as the seed nucleation layer, improving both the morphology of the nanorods and the performance of devices based upon them.
17.	Amin, G, et al. (författare) Scale-up synthesis of ZnO nanorods for printing inexpensive ZnO/polymer white light-emitting diode 2012 Ingår i: Journal of Materials Science_x000D_. ; 47, s. 4726-31 Tidskriftsartikel (refereegranskat)
18.	Asghar, M., et al. (författare) Characterization of deep acceptor level in as-grown ZnO thin film by molecular beam epitaxy 2014 Ingår i: Chinese Physics B. - : IOP Publishing. - 1674-1056. ; 23:9, s. 097101- Tidskriftsartikel (refereegranskat)abstract We report deep level transient spectroscopy results from ZnO layers grown on silicon by molecular beam epitaxy (MBE). The hot probe measurements reveal mixed conductivity in the as-grown ZnO layers, and the current-voltage (I-V) measurements demonstrate a good quality p-type Schottky device. A new deep acceptor level is observed in the ZnO layer having activation energy of 0.49 +/- 0.03 eV and capture cross-section of 8.57 +/- 10(-18) cm(2). Based on the results from Raman spectroscopy, photoluminescence, and secondary ion mass spectroscopy (SIMS) of the ZnO layer, the observed acceptor trap level is tentatively attributed to a nitrogen-zinc vacancy complex in ZnO.
19.	Atif, M., et al. (författare) RETRACTED: Effect of Urea on the Morphology of Fe3O4 Magnetic Nanoparticles and Their Application in Potentiometric Urea Biosensors 2019 Ingår i: Silicon. - : SPRINGER. - 1876-990X .- 1876-9918. ; 11:3, s. 1371-1376 Tidskriftsartikel (refereegranskat)abstract The effect of different concentrations of urea on the morphology of iron oxide (Fe3O4) magnetic nanoparticles was studied. Fe3O4 magnetic nanoparticles were fabricated by the coprecipitation method. The morphology, crystallinity, compositional purity, and emission characteristics were tested by the techniques of scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and Raman characterization. The drop-casting technique was successfully used to fabricate a potentiometric urea biosensor producing initially isopropanol and chitosan solution, consisting of Fe3O4 nanoparticles, on a glass fiber filter. To measure the developed biosensors voltage signal from the functionalized nanoparticles, a copper wire was utilized. The Fe3O4 nanoparticle surface functionalization was performed through the electrostatic immobilization of urease with the Fe3O4-chitosan (CH) nanobiocomposite. The presented urea biosensor measured a wide logarithmic range of urea concentration of 0.1-80 mM with a sensitivity of 42 mV/decade, and indicated a fast response time of approximately 12 s. The developed urea biosensor showed enhanced sensitivity, stability, reusability, and specificity. All experimental results demonstrate the application potential of the developed urea sensor for the monitoring of urea concentrations in human serum, drugs, and food industry-related samples.
20.	Atif, M., et al. (författare) The synthesis and optical characterization of well aligned ZnO nanorods using seed layer of Mn3O4 nanoparticles 2014 Ingår i: Optoelectronics and Advanced Materials Rapid Communications. - : National Institute of Optoelectronics.. - 1842-6573 .- 2065-3824. ; 8:7-8, s. 643-646 Tidskriftsartikel (refereegranskat)abstract In this study, vertically aligned ZnO nanorods were fabricated by hydrothermal growth method using manganese oxide Mn3O4 nanoparticles as a seed layer. X-ray diffraction and Raman studies have shown the nano meter size of Mn3O4 nanoparticles. ZnO nanorods were characterized by field emission scanning electron microscopy and X-ray diffraction techniques. The prepared ZnO nanorods are highly dense, uniform and verily aligned and possess good crystal quality. Photoluminescence analysis has demonstrated that the ZnO nanorods exhibit deep level emission in green region due to oxygen vacancy related emission and the orange/red region is resulted due to interstitial oxygen defects related emission. This method for the fabrication of well aligned ZnO nanorods can be adapted for the development of optoelectronic devices.
21.	Berglund, M, et al. (författare) [Pharmacological treatment of alcohol dependence. Acamprosate and naltrexone offer new approach] 1997 Ingår i: Lakartidningen. - 0023-7205. ; 94:30-31, s. 2645-8 Tidskriftsartikel (refereegranskat)
22.	Bruce, S, et al. (författare) Development, implementation and verification of a physics-based Si/SiGe HBT model for millimeter-wave non-linear circuit simulations 1996 Ingår i: Proceedings 26th European Microwave Conference, Prague, Czech Republic. ; , s. 903-905 Konferensbidrag (övrigt vetenskapligt/konstnärligt)
23.	Dawi, E. A., et al. (författare) Ag/AgCl Decorated Ionic Liquid@Tantalum Pentoxide Nanostructures: Fabrication, Photocatalytic Activity, and Cytotoxicity Effects Against Human Brain Tumor Cells 2023 Ingår i: JOURNAL OF INORGANIC AND ORGANOMETALLIC POLYMERS AND MATERIALS. - : SPRINGER. - 1574-1443. ; 33, s. 2647-2660 Tidskriftsartikel (refereegranskat)abstract Environmental contaminants have become a major concern for human beings due to their adverse effects on drinking water quality. Heterogeneous photocatalysis has been extensively investigated as a potential strategy to minimize the consequences of as-related processes. Using a room-temperature ionic liquid-mediated co-precipitation method, Ag@AgCl nanoparticles were loaded onto tantalum pentoxide to make a plasmonic photocatalyst to remove Congo Red dye. The physicochemical properties of the photocatalysts were characterized by X-ray diffraction powder (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), Diffuse Reflectance Spectroscopy (DRS), Fourier-transform infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM), photoluminescence (PL), and nitrogen adsorption-desorption isotherms. The results indicate that 96% of the dye was degraded within 20 min with a rate constant of 0.14 min(-1). The key radicals involved in the photocatalysis, recognized as O-2(center dot-) species, were identified by electron spin resonance (ESR) in the presence of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), as the spin trapping agent. Our findings and quenching experiments elucidates the mechanism of the charge carrier migration. The cytotoxicity activity of the nanostructures was also examined against human brain glioblastoma tumor cells for the first time. A precise analysis of the cell death pathway was conducted using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and caspase activity assays in combination with fluorescence microscopy images. The prepared nanomaterials were found to be promising candidates for treating the organic pollutants and biomedical waste effluents from academic and industrial activities.
24.	Fakhar-E-Alam, M., et al. (författare) Anticancer effects of nanometallic oxides and their ligands with photosensitizers in osteosarcoma cells 2015 Ingår i: Journal of Optoelectronics and Advanced Materials. - : NATL INST OPTOELECTRONICS. - 1454-4164 .- 1841-7132. ; 17:11-12, s. 1808-1815 Tidskriftsartikel (refereegranskat)abstract We studied the cytotoxic effects in Osteosarcoma (U2OS) cells to different nanosized metallic oxides e.g. zinc oxide nanowires (ZnO-NRs), manganese di-oxide nanowires (MnO2 NWs), ferric oxide nanoparticles (Fe2O3 NPs) individually and their connplexed forms with photosensitizers photofrin (R), 5-Aminolevulinic acid (5-ALA), and protoporphyrin IX (Pp IX). Cellular toxicity was assayed by cellular morphology, reactive oxygen species (ROS) detection, MTT assay under ultraviolet (UV), visible light and laser exposed conditions. Prominent cell death with above cited nanomaterials in their complexed forms with Photosensitizer was observed in labeled U2OS cells. This cell death might be due to their synergetic effect via the release of singlet oxygen species in Osteosarcoma cells showing their anticancer-cell effects.
25.	Fakhar-e-Alam, M, et al. (författare) Erratum: “Phototoxic Effects of Zinc Oxide Nanowires (ZnO NWs) Complexed with 5-ALA in RD Cell Line” (Laser Physics 21, 2165 (2011)) 2012 Ingår i: Laser physics. - : MAIK Nauka/Interperiodica. - 1054-660X .- 1555-6611. ; 22:1, s. 338-338 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract n/a
26.	Fakhar-e-Alam, M, et al. (författare) Erratum: “Phototoxic effects of zinc oxide nanowires (ZnO NWs) complexed with 5-ALA in RD cell line” (Laser Physics 21, 2165 (2011)) 2012 Ingår i: Laser physics. - : M A I K Nauka - Interperiodica. - 1054-660X .- 1555-6611. ; 22:2, s. 476-476 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract n/a
27.	Fakhar-e-Alam, M., et al. (författare) Phototoxic effects of zinc oxide nanowires (ZnO NWs) complexed with 5-ALA in RD cell line 2011 Ingår i: Laser physics. - : MAIK Nauka/Interperiodica. - 1054-660X .- 1555-6611. ; 21:12, s. 2165-2170 Tidskriftsartikel (refereegranskat)abstract In this current study, we have manifested the photosensitizing effects of zinc oxide nanowires (ZnO NWs) in dark as well as under ultra violet light exposure with 240 nm of UV region, using human muscle cancer (Rhybdomyosarcoma cells, RD) as in vitro experimental model. We have fabricated ZnO-NWs on the tip of borosilicate glass capillaries (0.5 mu m diameter) and were conjugated using 5-aminolevulinic acid (ALA) for the efficient intracellular drug delivery. When ZnO NWs were applied on tumor localizing drugs with non ionizing illumination, then excited drug liberates reactive oxygen species (ROS), effecting mitochondria and nucleus resulting in cell necrosis within few minutes. During investigations, we observed that when ZnO-NWs grown on intracellular tip was excited by using 240 nm of UV light, as a resultant 625 nm of emitted red light were used as appetizer in the presence of 5-ALA for chemical reaction, which produces singlet oxygen, responsible for cell necrosis. Morphological changes of necrosed cells were examined under microscopy. Moreover, Viability of controlled and treated RD cells with optimum dose of light (UV-Visible) has been assessed by MTT assay as well as reactive oxygen species (ROS) detection.
28.	Ferreira Da Silva, A., et al. (författare) Growth, optical characterization and modeling of ZnO nanorods on Si, SiC and macroporous si structure 2009 Ingår i: Technical Proceedings of the 2009 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2009. - : CRC Press. - 9781439817834 - 9781439817841 ; , s. 206-209 Konferensbidrag (refereegranskat)abstract Zinc Oxide (ZnO) and Silicon Carbide (SiC) are prominent materials with large applicability such as optoelectronic nanodevices and for instance ultraviolet detectors. There is lack of important information about optical transitions beyond the indirect band gap energy (BGE) of 4H-SÍC and even more for ZnO direct BGE grown on the former material. Using vapor-liquid-solid and the aqueous chemical growth methods we have grown ZnO nanorods on different substrates, such as quartz, n- and p-type porous silicon, and n-type 4H-SÍC. Scanning electron microscopy (SEM) was employed to compare sample morphologies. The absorption was calculated employing a projector augmented wave (PAW) method. The measured absorption of ZnO nanorods, on different substrates, is lower than that observed for ZnO films on quartz substrate, in the low energy spectral range. It is observed a strong effect of 4H-SÍC substrates on ZnO nanorod properties. Experiment and theory show a good agreement when the shape of the optical absorption is considered for both materials.
29.	Hussain Ibupoto, Zafar, et al. (författare) Well aligned ZnO nanorods growth on the gold coated glass substrate by aqueous chemical growth method using seed layer of Fe3O4 and Co3O4 nanoparticles 2013 Ingår i: Journal of Crystal Growth. - : Elsevier. - 0022-0248 .- 1873-5002. ; 368, s. 39-46 Tidskriftsartikel (refereegranskat)abstract In this study, Fe3O4 and Co3O4 nanoparticles were prepared by co-precipitation method and sol-gel method respectively. The synthesised nanoparticles were characterised by X-ray diffraction [XRD] and Raman spectroscopy techniques. The obtained results have shown the nanocrystalline phase of obtained Fe3O4 and Co3O4 nanoparticles. Furthermore, the Fe3O4 and Co3O4 nanoparticles were used as seed layer for the fabrication of well-aligned ZnO nanorods on the gold coated glass substrate by aqueous chemical growth method. Scanning electron microscopy (SEM), high resolution transmission electron microscopy [HRTEM], as well as XRD and energy dispersive X-ray techniques were used for the structural characterisation of synthesised ZnO nanorods. This study has explored highly dense, uniform, well-aligned growth pattern along 0001 direction and good crystal quality of the prepared ZnO nanorods. ZnO nanorods are only composed of Zn and O atoms. Moreover, X-ray photoelectron spectroscopy was used for the chemical analysis of fabricated ZnO nanorods. In addition, the structural characterisation and the chemical composition study and the optical investigation were carried out for the fabricated ZnO nanorods and the photoluminescence [PL] spectrum have shown strong ultraviolet (UV) peak at 381 nm for Fe3O4 nanoparticles seeded ZnO nanorods and the PL spectrum for ZnO nanorods grown with the seed layer of Co3O4 nanoparticles has shown a UV peak at 382 nm. The green emission and orange/red peaks were also observed for ZnO nanorods grown with both the seed layers. This study has indicated the fabrication of well aligned ZnO nanorods using the one inorganic nanomaterial on other inorganic nanomaterial due to their similar chemistry.
30.	Kashif, M, et al. (författare) Characterisation, analysis and optical properties of nanostructure ZnO using the sol-gel method 2012 Ingår i: Micro & Nano Letters. - : Institution of Engineering and Technology (IET). - 1750-0443. ; 7:2, s. 163-167 Tidskriftsartikel (refereegranskat)abstract Nanostructure ZnO was grown on thin aluminium layer, deposited on silicon substrate using the sol-gel method. The surface morphologies of nanostructure ZnO at different precursor concentrations were studied using scanning electron microscopy. Raman spectroscopy suggested that nanorods started to grow along with nanoflakes at a precursor concentration of 50 mM and the density of the nanorods significantly increases when the concentration was raised to 75 mM. Raman spectra were intensified and red shifted with the increment of precursor concentration. Optical properties of refractive index and optical dielectric constant are investigated. The structural defects at lower level of precursor were probably due to the hypoxic environment, whereas the red shift of Raman spectra was due to the structural change of ZnO nanocrystals.
31.	Kashif, M., et al. (författare) Morphological, optical, and Raman characteristics of ZnO nanoflakes prepared via a sol-gel method 2012 Ingår i: PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE. - : Wiley-VCH Verlag Berlin. - 1862-6300. ; 209:1, s. 143-147 Tidskriftsartikel (refereegranskat)abstract Two-dimensional (2D) ZnO nanoflakes were grown on thin aluminum layer, deposited on silicon substrate, using a sol-gel method. The surface morphologies of ZnO nanoflakes at different precursor concentrations were studied using scanning electron microscopy (SEM). Combined studies of SEM, photoluminescence (PL), and Raman spectroscopy suggested that nanorods started to grow along with nanoflakes at a precursor concentration of 0.05 M and the density of the nanorods significantly increased when the concentration was raised to 0.075 M. Both the UV-luminescence and Raman spectra were intensified and redshifted with the increment of precursor concentration. Spectral intensification suggests improvement in crystal qualities and better optical properties of the fabricated ZnO nanostructures. The structural defects at lower levels of precursor were probably due to the hypoxic environment, whereas, the redshift of PL and Raman spectra was due to the local heating of ZnO nanocrystals.
32.	Khun, Kimleang, et al. (författare) Potentiometric glucose sensor based on the glucose oxidase immobilized iron ferrite magnetic particle/chitosan composite modified gold coated glass electrode 2012 Ingår i: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 173, s. 698-703 Tidskriftsartikel (refereegranskat)abstract A potentiometric glucose sensor based on the glucose oxidase immobilized on iron ferrite (Fe3O4) nanoparticles/chitosan composite modified gold coated glass substrate was fabricated. The electrode has advantages of both the inorganic Fe3O4 magnetic nanoparticles and the organic substance chitosan. The freshly prepared iron ferrite magnetic nanoparticles were characterized by X-ray diffraction (xRD) and transmission electron microscopy (TEM) technique was used for the analysis of dispersed iron ferrite magnetic nanoparticles in the mixture of glucose oxidase and chitosan. The electrostatic interaction of Fe3O4 nanoparticles with chitosan and the glucose oxidase molecules was investigated by the infra-red reflection absorption spectroscopy (IRAS) study. The glucose oxidase enzyme was immobilized on the surface of iron ferrite/chitosan composite without the use of Nafion or cross linker molecules. The fabricated glucose sensor has shown acceptable potentiometric response for the wide range of glucose concentrations from 1.0 x 10(-6) to 3.0 x 10(-2) M. The sensor electrode showed a sensitivity of 27.3 +/- 0.8 mV/decade and also fast response time of 7.0s. Moreover, the present glucose sensor has demonstrated good reproducibility, repeatability, selectivity and the storage stability. All the obtained results indicated that the glucose sensor based on the glucose oxidase immobilized iron ferrite/chitosan composite modified gold coated glass electrode can be used for the monitoring of glucose concentrations in human serum, drugs and may be applicable to detect glucose in the presence of other analytes.
33.	Kishwar, Sultana, et al. (författare) Biotoxicity of nanometallic oxides and their ligands with photosensitizers in osteosarcom a cells Annan publikation (övrigt vetenskapligt/konstnärligt)abstract The cytotoxic effects in osteosarcoma (U2OS) cells to different nanosized metallic oxides e.g. zinc oxide nanowires (ZnO-NWs), manganese di-oxide nanowires (MnO2 NWs), ferric oxide nanoparticles (Fe2O3 NPs) individually and their complex forms with photosensitizers photofrin®, 5-Aminolevulinic acid (5-ALA), and protoporphyrin IX (Pp IX) were studied. The cellular effects were assayed by analyzing the cellular morphology. The reactive oxygen species (ROS) were detected using 2', 7'-Dichlorofluorescein diacetate, and cell viability were assessed using MTT assay under ultraviolet (UV), visible light and laser exposed conditions. Prominent cell death with above cited nanomaterials in their complex forms with photosensitizer was observed in labeled U2OS cells. This cell death might be due to their synergetic effect via the release of singlet oxygen species in osteosarcoma cells showing their anticancer-cell effects.
34.	Klason, Peter, 1977, et al. (författare) Characterization of white light emitting diodes based on ZnO nanostructures grown on p-Si. 2007 Ingår i: Procc. ENS. Konferensbidrag (övrigt vetenskapligt/konstnärligt)
35.	Klason, Peter, 1977, et al. (författare) Fabrication and characterization of p-Si/n-ZnO heterostructured junctions 2008 Ingår i: Microelectronics Journal. Tidskriftsartikel (refereegranskat)abstract In this paper ZnO nanorods and nanodots (with and without a SiO2 buffer layer) were grown on p-Si, forming p–n heterojunctions. The nanorod devices showed no visible electroluminescence (EL) emission but showed rectifying behavior. Covering around 60% of the length of the nanorods with PMMA produced an ideality factor of 3.91±0.11 together with a reverse saturation current of View the MathML source. Up to two orders of magnitude rectification was observed for the current at bias -3 and 3 V. The nanodot devices showed EL emission under forward bias conditions. It seems that the buffer layer increased both the stability and efficiency of the devices, since the buffer layer device could operate at larger applied voltage and showed EL emission under reverse bias.
36.	Klason, P, et al. (författare) Fabrication and characterization of p-Si/n-ZnO heterostructured junctions 2009 Ingår i: MICROELECTRONICS JOURNAL. - : Elsevier BV. - 0026-2692. ; 40:4-5, s. 706-710 Tidskriftsartikel (refereegranskat)abstract In this paper ZnO nanorods and nanodots (with and without a SiO2 buffer layer) were grown on p-Si, forming p-n heterojunctions. The nanorod devices showed no visible electroluminescence (EL) emission but showed rectifying behavior. Covering around 60% of the length of the nanorods with PMMA produced an ideality factor of 3.91 +/- 0.11 together with a reverse saturation current of 6.53 +/- 4.2 x 10(-8) A. Up to two orders of magnitude rectification was observed for the current at bias -3 and 3 V. The nanodot devices showed EL emission under forward bias conditions. It seems that the buffer layer increased both the stability and efficiency of the devices, since the buffer layer device could operate at larger applied voltage and showed EL emission under reverse bias.
37.	Mustafa, Elfatih Mohammed, et al. (författare) Efficient CuO/Ag2WO4 photoelectrodes for photoelectrochemical water splitting using solar visible radiation 2023 Ingår i: RSC Advances. - : ROYAL SOC CHEMISTRY. - 2046-2069. ; 13:17, s. 11297-11310 Tidskriftsartikel (refereegranskat)abstract Water splitting energy production relies heavily on the development of high-performance photoelectrochemical cells (PECs). Among the most highly regarded semiconductor materials, cupric oxide (CuO) is an excellent photocathode material. Pristine CuO does not perform well as a photocathode due to its tendency to recombine electrons and holes rapidly. Photocathodes with high efficiency can be produced by developing CuO-based composite systems. The aim of our research is to develop an Ag2WO4/CuO composite by incorporating silver tungstate (Ag2WO4) nanoparticles onto hydrothermally grown CuO nanoleaves (NLs) by successive ionic layer adsorption and reaction (SILAR). To prepare CuO/Ag2WO4 composites, SILAR was used in conjunction with different Ag2WO4 nanoparticle deposition cycles. Physicochemical characterization reveals well-defined nanoleaves morphologies with tailored surface compositions. Composite CuO/Ag2WO4 crystal structures are governed by the monoclinic phase of CuO and the hexagonal phase of Ag2WO4. It has been demonstrated that the CuO/Ag2WO4 composite has outstanding performance in the PEC water splitting process when used with five cycles. In the CuO/Ag2WO4 photocathode, water splitting activity is observed at low overpotential and high photocurrent density, indicating that the reaction takes place at low energy barriers. Several factors contribute to PEC performance in composites. These factors include the high density of surface active sites, the high charge separation rate, the presence of favourable surface defects, and the synergy of CuO and Ag2WO4 photoreaction. By using SILAR, silver tungstate can be deposited onto semiconducting materials with strong visible absorption, enabling the development of energy-efficient photocathodes.
38.	Ouacha, H, et al. (författare) Impact of plasma etching on the noise performance of Ti/p-Si and Ti/p-Si1-xGex Schottky contacts 2000 Ingår i: Journal of Applied Physics. - 0021-8979 .- 1089-7550. ; 87:8, s. 3858-3863 Tidskriftsartikel (refereegranskat)abstract The effect of plasma etching on the noise properties of Ti/p-Si and Ti/p-Si1-xGex (with x=0.05) Schottky junctions has been investigated. The noise measurements were performed over a temperature range of 77-300 K at frequencies of 10-100 kHz. The main noise source observed in these diodes during argon plasma sputter etching was attributed to the generation-recombination noise. From the analysis of the noise data, we have determined the interface state density and evaluated the introduced damage. The results indicate two optimum operating temperatures where low-noise level can be achieved. Furthermore, the activation energies of trap levels have been extracted by using noise spectroscopy (NS) and compared with those measured by deep-level transient spectroscopy (DLTS). We found two additional trap states using NS not detected by DLTS measurements. Finally, a noise comparison between Ti/p-Si and Ir/p-Si fabricated on an unetched substrate has been made. (C) 2000 American Institute of Physics. [S0021-8979(00)00608-3].
39.	Ouacha, H., et al. (författare) Noise properties of an individual and two crossing multiwalled carbon nanotubes 2002 Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 80:6, s. 1055- Tidskriftsartikel (refereegranskat)
40.	Peto, G, et al. (författare) Formation of epitaxial CoSi2 films on Si and on Si/Si80Ge20 (100) by reactive deposition epitaxy 2002 Ingår i: Applied Physics Letters. - : American Institute of Physics. - 0003-6951 .- 1077-3118. ; 81:1, s. 37-39 Tidskriftsartikel (refereegranskat)abstract CoxTi1-x layers were deposited on Si (100) and on Si/Si80Ge20 (100) capped with 30- or 40-nm-thick Si at 650 degreesC substrate temperature at 1x10(-6) Pa pressure. The Co-silicide films grown by reactive deposition epitaxy were characterized by Rutherford backscattering-channeling, x-ray difraction, by depth profile analysis of the components, and by sheet resistance measurements. The Ti content of the deposited Co layers was between 0.1 and 8 at. %. The epitaxy of the layers on Si and on Si/Si80Ge20 improved by increasing the Ti concentration. The minimum yield of the channeling and the full width at half maximum value of the rocking curve of CoSi2 decreased. The sheet resisitance of the formed layers was also minimal in these cases. The method applied is promising to form epitaxial CoSi2 layers on SixGe1-x substrates.
41.	Rahman, M. M., et al. (författare) Fabrication and characterization of white light emitting diode based on ZnO nanorods grown on p-Si 2008 Konferensbidrag (refereegranskat)
42.	Rahman, M. M., et al. (författare) Fabrication and characterization of white light emitting diode based on ZnO nanorods on p-Si 2008 Ingår i: 8th IEEE Conference on Nanotechnology, 2008. NANO '08.. - Piscataway, NJ, USA : IEEE. - 9781424421039 - 9781424421046 ; , s. 51-54 Konferensbidrag (refereegranskat)abstract Recently zinc oxide (ZnO) has drawn attention as it exhibits promising properties for making optoelectronic devices, biosensors. In this paper we will present our recent results from research work on the fabrication of light emitting diodes (LEDs) based on n-ZnO nanorods grown on p-Si by a low temperature chemical approach. The ideality factor of the p- Si/n-ZnO junctions was found to be 5.47+0.67. The high value is probably due to the presence of surface state. Structural, electrical and optical characterization from different processed LEDs will be presented and analyzed.
43.	Rydberg, A, et al. (författare) Multi-mode operation of antenna integrated microwave quantum well-diode oscillator 1994 Ingår i: Microwave and Optimal Technology Letters. ; 7, s. 43-45 Tidskriftsartikel (refereegranskat)
44.	Savoyant, A., et al. (författare) Light-induced high-spin state in ZnO nanoparticles 2020 Ingår i: Nanotechnology. - : IOP PUBLISHING LTD. - 0957-4484 .- 1361-6528. ; 31:9 Tidskriftsartikel (refereegranskat)abstract The effects of white-light irradiation on similar to 15.nm diameter ZnO nanoparticles are investigated by means of electron paramagnetic resonance, near liquid-nitrogen and liquid-helium temperatures. Under dark conditions, usual core- and surface-defects are detected, respectively, at g = 1.960 and g = 2.003. Under white-light illumination, the core-defect signal intensity is strongly increased, which is to be correlated to the light-induced conductivitys augmentation. Beside, a four-lines structure appears, with the same gravity center as that of the surface defects. Simulations and intensity power-dependence measurements show that this four-line-structure is very likely to arise from a localized high spin S = 2, induced by light irradiation, and subjected to a weak axial anisotropy. At 85K, this high-spin state can last several hours after the light-irradiation removal, probably due to highly spin-forbidden recombination process. The possible excited resonant complexes at the origin of this signal are discussed. Other light-induced S = 1/2-like centers are detected as well, which depend on the nanoparticles growth conditions.
45.	Svensson, B. G., et al. (författare) Hydrothermally grown singlecrystalline zinc oxide; characterization and modification 2008 Ingår i: Procc. MRS. - USA : Material Research Society. Konferensbidrag (refereegranskat)
46.	Tobin, G, et al. (författare) VH gene mutation analysis distinguishes a subgroup of chronic lymphocytic leukemia with low-mutated VH genes and inferior outcome. Tidskriftsartikel (refereegranskat)
47.	Toropov, A.A., et al. (författare) Excitons as a probe of interface morphology in Cd(Zn)Se/ZnSe heterostructures 2000 Ingår i: Applied Surface Science. - 0169-4332 .- 1873-5584. ; 166:1, s. 278-283 Tidskriftsartikel (refereegranskat)abstract We present studies of the excitonic spectrum in superlattices (SLs) of CdSe insertions in a ZnSe matrix aimed at elucidating the CdSe/ZnSe interface morphology. The experimental photoluminescence excitation spectra are compared with the results of variational exciton calculations performed within the effective mass approximation. The shape of the average vertical (along the SL growth axis) distribution of CdSe within each insertion, used in the calculations, was obtained from a theoretical simulation of X-ray diffraction (XRD) rocking curves measured in the same samples. The results indicate that the thinnest layers are graded composition ZnCdSe quantum wells (QWs), generally homogeneous in the layer planes, whereas flat islands enriched by Cd appear at the CdSe nominal thickness larger than 0.5-0.6 monolayer (ML).
48.	ul Hasan, K, et al. (författare) Polycation stabilization of graphene suspensions 2011 Ingår i: Nanoscale Research Letters. ; 3, s. 493- Tidskriftsartikel (refereegranskat)
49.	Vincent, Jonathan, et al. (författare) Theory of a room-temperature silicon quantum dot transitor as a sensitive electrometer 2004 Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 95, s. 323- Tidskriftsartikel (refereegranskat)abstract We consider theoretically the use of a room-temperature silicon quantum dot based device for electrometer applications. The low power device includes two split gates that quantize the electronic energy levels in the emitter and collector regions. The base consists of a silicon quantum dot buried in silicon dioxide. The small size of the dot and quantization of the states in the leads combined to allow the device to operate at room temperature. The nonlinear current–voltage characteristics can be significantly altered by small changes to the potential of the split gates. Power dissipation in the device therefore changes with the split gate voltage, and this can be exploited in electrometer applications. A simple model of the power dissipated when the device is part of a microwave resonant inductor-resistor-capacitor tank circuit suggests that large changes in device power can be achieved by changing the gate voltage, thereby forming a measurable signal. We also demonstrate that the power dissipation in the device changes as the base width is varied, and that the current through the device increases exponentially with a decrease in base width.
50.	Willander, Magnus, et al. (författare) Applications of Zinc Oxide Nanowires for Bio-photonics and Bio-electronics 2011 Ingår i: Proceedings of SPIE Volume 7940. - Bellingham, Washington, USA : SPIE - International Society for Optical Engineering. - 9780819484772 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Using zinc oxide (ZnO) nanostructures, nanorods (NRs) and nanoparticles (NPs) grown on different substrates (sub-micrometer glass pipettes, thin silver wire and on plastic substrate) different bio-sensors were demonstrated. The demonstrated sensors are based on potentiometric approach and are sensitive to the ionic metals and biological analyte in question. For each case a selective membrane or enzyme was used. The measurements were performed for intracellular environment as well as in some cases (cholesterol and uric acid). The selectivity in each case is tuned according to the element to be sensed. Moreover we also developed photodynamic therapy approach based on the use of ZnO NRs and NPs. Necrosis/apoptosis was possible to achieve for different types of cancerous cell. The results indicate that the ZnO with its UV and white band emissions is beneficial to photodynamic therapy technology.

Skapa referenser, mejla, bekava och länka

Länka till träfflistan

Träfflista för sökning "WFRF:(Willander M.) "

Avgränsa träffmängd

År