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  • 1.
    Ali, A.
    et al.
    Riphah Int University, Pakistan.
    Israr-Qadir, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Wazir, Z.
    Riphah Int University, Pakistan.
    Tufail, M.
    Riphah Int University, Pakistan.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Jamil-Rana, Sadaf
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Atif, M.
    King Saud University, Saudi Arabia; National Institute Lasers and Optron, Pakistan.
    Khan, S. A.
    National Centre Phys, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Cobalt oxide magnetic nanoparticles-chitosan nanocomposite based electrochemical urea biosensor2015In: Indian Journal of Physics, ISSN 0973-1458, E-ISSN 0974-9845, Vol. 89, no 4, p. 331-336Article in journal (Refereed)
    Abstract [en]

    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.

  • 2.
    Batool, S S
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Imran, Z
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. Pakistan Inst. Engn. and Appl Sci, Pakistan.
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Usman, M
    Pakistan Institute Engn and Appl Science, Pakistan .
    Jamil, H
    Pakistan Institute Engn and Appl Science, Pakistan .
    Rafiq, M A
    Pakistan Institute Engn and Appl Science, Pakistan .
    Hasan, M M
    Pakistan Institute Engn and Appl Science, Pakistan .
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Silica nanofibers based impedance type humidity detector prepared on glass substrate2013In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 87, p. 1-6Article in journal (Refereed)
    Abstract [en]

    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.

  • 3.
    Imran, Z.
    et al.
    Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan.
    Batool, S. S.
    Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan.
    Jamil, H.
    Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan.
    Usman, M.
    Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan.
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Shah, S. H.
    PINSTECH, Islamabad, Pakistan.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Rafiq, M. A.
    Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan.
    Hasan, M. M.
    Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Excellent humidity sensing properties of cadmium titanate nanofibers2013In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 39, no 1, p. 457-462Article in journal (Refereed)
    Abstract [en]

    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.

  • 4.
    Israr, Muhammad Qadir
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Sadaf, Jamil Rana
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Larsson, L. A.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Holtz, Per-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Natural oxidation based controlled synthesis and characterization of ZnO nanodisks through structural transition of ZnO nanorods at 55 °CManuscript (preprint) (Other academic)
    Abstract [en]

    A novel, reproducible and natural oxidation based low temperature (55 °C) synthesis of ZnO nanodisks has been carried out using metallic zinc foil and formamide solution. The concentration of the formamide and the reaction duration are optimized to achieve the controlled fabrication. The morphological evolution of the ZnO nanodisks has been observed using scanning electron microscopy, energy dispersive spectroscopy and transmission electron microscopy. It is observed that ZnO nanodisks are of a good crystalline quality and have hexagonal wurtzite structure. The mechanism behind the growth and the breaking of nanorods into nanodisks is also suggested. Microphotoluminescence spectrum exhibits a strong ultraviolet emission and a very weak deep level related emission. In addition, temperature dependent studies reveal a decrease in the emission intensity of the ultraviolet peak combined with a red shift with increasing temperature from 20 to 300 K.

  • 5.
    Israr, Muhammad Qadir
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    ul Hasan, Kamran
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Sadaf, Jamil Rana
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Engquist, Isak
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Danielsson, B.
    Pure and Applied Biochemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
    Structural characterization and biocompatible applications of graphene nanosheets for miniaturization of potentiometric cholesterol biosensor2011In: Journal of Biosensors & Bioelectronics, ISSN 2155-6210, Vol. 2, no 3Article in journal (Refereed)
    Abstract [en]

    The potentiometric cholesterol biosensor based on graphene nanosheets has been successfully miniaturized. Cholesterol oxidase (ChOx) has been immobilized onto graphene nanosheets exfoliated on copper wire through the process of physical adsorption,. The presented potentiometric biosensor renders effective selectivity and sensitivity (~82 mV/decade) for the detection of cholesterol biomolecules in 1 × 10−6 M to 1 × 10−3 M logarithmic range and quick output response within ~ 4 sec. The stability and reusability of the biosensor has also been investigated for the above mentioned range of cholesterol concentrations. The enzyme activity measurements on graphene nanosheets are studied using UV-Visible and FTIR spectrophotometers. Additionally, the functioning of the presented biosensor is studied for a range of temperatures (15-70 °C) and pH values (4-9).

  • 6.
    Israr, Muhammed Qadir
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Sadaf, Jamil Rana
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Yang, Li-Li
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Palisaitis, Justinas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Persson, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Trimming of aqueous chemically grown ZnO nanorods into ZnO nanotubes and their comparative optical properties2009In: APPLIED PHYSICS LETTERS, ISSN 0003-6951, Vol. 95, no 7, p. 073114-Article in journal (Refereed)
    Abstract [en]

    Highly oriented ZnO nanotubes were fabricated on a silicon substrate by aqueous chemical growth at low temperature (andlt; 100 degrees C) by trimming of ZnO nanorods. The yield of nanotubes in the sample was 100%. Photoluminescence spectroscopy of the nanotubes reveals an enhanced and broadened ultraviolet (UV) emission peak, compared with the initial nanorods. This effect is attributed to whispering gallery mode resonance. In addition, a redshift of the UV emission peak is also observed. Enhancement in the deep defect band emission in the nanotubes compared to nanorods was also manifested as a result of the increased surface area.

  • 7.
    Israr Qadir, Muhammad
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Larsson, L.A.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Holtz, Per-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Fabrication of ZnO nanodisks from structural transformation of ZnO nanorods through natural oxidation and their emission characteristics2014In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 40, no 1, p. 2435-2439Article in journal (Refereed)
    Abstract [en]

    An environmentally benign natural oxidation based synthetic technique has been developed to grow and transform the ZnO nanorods into nanodisks at a very mild temperature of 55 degrees C with excellent features of its novelty and reproducibility. Metallic zinc foil and formamide solution have been utilized as substrate and reacting solution, respectively, for the growth of ZnO nanostructures. The optimized values of temperature, concentration of formamide and the reaction time are achieved to obtain the controlled and desired nanoscale morphologies. Detailed mechanism of the structural transformation of the nanorods into nanodisks has been discussed. Strong ultraviolet emission peak along with the much weaker deep level defects related emission has been realized in the microphotoluminescence spectrum. A visible red-shift and decrease in the intensity of ultraviolet peak are observed with increasing range of temperature from 20 to 300 K.

  • 8.
    Israr Qadir, Muhammad
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Cathodoluminescence characterization of ZnO nanorods synthesized by chemical solution and of its conversion to ellipsoidal morphology2014In: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 29, no 20, p. 2425-2431Article in journal (Refereed)
    Abstract [en]

    A facile and reproducible low-temperature (80 degrees C) solution route has been introduced to synthesize ZnO ellipsoids on silicon substrate without any pretreatment of the substrate or organic/inorganic additives. Scanning electron microscopy, transmission electron microscopy, and x-ray diffraction spectroscopy are performed to analyze the structural evolution, the single crystalline nature, and growth orientation at different stages of the synthetic process. The sequential formation mechanisms of heterogeneous nucleation in primary and secondary crystal growth behaviors have been discussed in detail. The presented results reveal that the morphology of micro/nanostructures with desired features can be optimized. The optical properties of grown structures at different stages were investigated using cathodoluminescence (CL). The monochromatic CL images were recorded to examine the UV and visible band emission contributions from the different positions of the intermediate and final structures of the individual ZnO ellipsoid. Significant enhancement in the defect level emission intensity at the central position of the structure reveals that the quality of the material improves as the reaction time is extended.

  • 9.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Chemically Synthesized ZnO Nanostructures: Realization of White Optoelectronic Devices with High CRI Values2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Recently in a couple of decades, nanotechnology and nanoscience are becoming wide spread fields of research due to the revolutionary advances in the manufacturing processes which enable the realization of infinitesimally modest nanodevices holding a huge variety of fascinating properties and applications. Besides various functional materials, ZnO has captivated interests for a variety of applications in electronics and optoelectronics owing to its unique characteristics; such as, direct wide band gap, large exciton binding energy, semiconducting, photonic, and piezoelectric properties. A distinguished capability of the ZnO material is the effortless synthesis of nanoscale structures with enormous assortments in their morphological and dimensional aspects. Regardless the significant developments in the fabrication of ZnO based homojunction optoelectronic nanodevices, the stable and reproducible p-type conductivity of ZnO material is still a challenge which is one of the paramount factors of the increasing interest for fabrication of heterojunction of ZnO nanostructures with other mainstream ptype semiconductors, such as Si, GaN, and organic materials.

    Herein, ZnO nanorods, nanotubes and nanoflowers have been synthesized by solution-based methodology at low temperature (<100 ˚C) and a thorough study on the applications of ZnO nanostructures as white light emitting diodes (LEDs) has been perceived. At the outset, ZnO nanotubes have been synthesized by the trimming of aqueous chemically grown ZnO nanorods with 100% yield and their comparative optical properties have been explored through photoluminescence study, and a profound enhancement in ultraviolet and visible emission is observed (paper I). ZnO nanotubes are further exploited for its promising application as an optoelectronic device. Pure white light emission is observed from the ZnO nanotubes/p-GaN based LED. To analyze the location of the recombination of electron–hole and current transport mechanisms, the EL characteristics of n-ZnO nanotubes/p-GaN heterostructure LED have been investigated under forward and reverse bias. The origin of distinctly different EL peaks under both configurations has been suggested and the influence of increasing values of temperature on the device characteristics is also studied under fixed applied current, in order to check its performance under harsh conditions and for practical  applications (paper II-III). Moreover, it is observed that ZnO-nanotubes/GaN heterostructure LED has an ability to produce an environmentally benign alternative of traditional lighting sources with high color rendering index (CRI) of 96 (paper IV). On the basis of EL, cathodoluminescence and transmission electron microscopy investigations; a robust correspondence has been established between the formation of radiative surface defect states in the nanotubes and the pure cool white light with appropriate color temperature. In paper V, a miniaturized white LED has been developed using Au/n-ZnO nanorods integrated on a glass pipette (having a sharp cylindrical tip with the diameter of 700 nm) which exhibits a broad EL band emission covering the whole visible spectrum range and a CRI value of 73. Besides one-dimensional ZnO nanostructures (nanorods and nanotubes), three-dimensional ZnO dahlia-flower nanoarchitectures have also been fabricated at room temperature relying on natural oxidation based aqueous chemically synthetic approach (paper VI).  Glycineassisted multi-oriented ZnO nanoflowers with highly large surface area to volume ratio have been synthesized on Zn foil substrate through the self-assembly of thin nano-petals as building blocks and polar surfaces of ZnO have been anticipated to be  stabilized through the adsorption of reactive hydroxyl and amide functions of glycine.

    List of papers
    1. Trimming of aqueous chemically grown ZnO nanorods into ZnO nanotubes and their comparative optical properties
    Open this publication in new window or tab >>Trimming of aqueous chemically grown ZnO nanorods into ZnO nanotubes and their comparative optical properties
    Show others...
    2009 (English)In: APPLIED PHYSICS LETTERS, ISSN 0003-6951, Vol. 95, no 7, p. 073114-Article in journal (Refereed) Published
    Abstract [en]

    Highly oriented ZnO nanotubes were fabricated on a silicon substrate by aqueous chemical growth at low temperature (andlt; 100 degrees C) by trimming of ZnO nanorods. The yield of nanotubes in the sample was 100%. Photoluminescence spectroscopy of the nanotubes reveals an enhanced and broadened ultraviolet (UV) emission peak, compared with the initial nanorods. This effect is attributed to whispering gallery mode resonance. In addition, a redshift of the UV emission peak is also observed. Enhancement in the deep defect band emission in the nanotubes compared to nanorods was also manifested as a result of the increased surface area.

    Keywords
    crystal growth from solution, II-VI semiconductors, nanofabrication, red shift, semiconductor growth, semiconductor nanotubes, whispering gallery modes, wide band gap semiconductors, zinc compounds
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-20618 (URN)10.1063/1.3211124 (DOI)
    Available from: 2009-09-16 Created: 2009-09-15 Last updated: 2015-03-09
    2. White Electroluminescence Using ZnO Nanotubes/GaN Heterostructure Light-Emitting Diode
    Open this publication in new window or tab >>White Electroluminescence Using ZnO Nanotubes/GaN Heterostructure Light-Emitting Diode
    Show others...
    2010 (English)In: NANOSCALE RESEARCH LETTERS, ISSN 1931-7573, Vol. 5, no 6, p. 957-960Article in journal (Refereed) Published
    Abstract [en]

    We report the fabrication of heterostructure white light-emitting diode (LED) comprised of n-ZnO nanotubes (NTs) aqueous chemically synthesized on p-GaN substrate. Room temperature electroluminescence (EL) of the LED demonstrates strong broadband white emission spectrum consisting of predominating peak centred at 560 nm and relatively weak violet-blue emission peak at 450 nm under forward bias. The broadband EL emission covering the whole visible spectrum has been attributed to the large surface area and high surface states of ZnO NTs produced during the etching process. In addition, comparison of the EL emission colour quality shows that ZnO nanotubes have much better quality than that of the ZnO nanorods. The colour-rendering index of the white light obtained from the nanotubes was 87, while the nanorods-based LED emit yellowish colour.

    Place, publisher, year, edition, pages
    Springer Science Business Media, 2010
    Keywords
    ZnO nanotubes, Light-emitting diodes, Electroluminescence, Lightning, White light sources
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-57167 (URN)10.1007/s11671-010-9588-z (DOI)000278096000008 ()
    Available from: 2010-06-11 Created: 2010-06-11 Last updated: 2014-09-25
    3. Forward- and reverse-biased electroluminescence behavior of chemically fabricated ZnO nanotubes/GaN interface
    Open this publication in new window or tab >>Forward- and reverse-biased electroluminescence behavior of chemically fabricated ZnO nanotubes/GaN interface
    Show others...
    2011 (English)In: SEMICONDUCTOR SCIENCE AND TECHNOLOGY, ISSN 0268-1242, Vol. 26, no 7, p. 075003-Article in journal (Refereed) Published
    Abstract [en]

    Electroluminescence characteristics of an n-ZnO nanotubes/p-GaN heterostructure light-emitting diode (LED) have been investigated at forward and reverse bias. Distinctly different emission spectra have been observed and the location of the recombination of electron-hole is analyzed under both configurations. The forward-biased emission spectrum shows two peaks centered at around 450 and 560 nm, while the reverse-biased spectrum exhibits a single emission peak at 650 nm. By comparing the current transport mechanisms, it is suggested that the violet-blue emission peak (450 nm) observed only under forward bias is originating from the heterojunction of the ZnO nanotubes/p-GaN LED. The influence on the emission intensity of the device with the increase in temperature at constant current is studied in the range from 25 to 65 degrees C, to check its compatibility for practical applications and under harsh conditions.

    Place, publisher, year, edition, pages
    Iop Publishing Ltd, 2011
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-67962 (URN)10.1088/0268-1242/26/7/075003 (DOI)000289554400004 ()
    Available from: 2011-05-04 Created: 2011-05-04 Last updated: 2014-01-15
    4. The correlation between radiative surface defect states and high color rendering index from ZnO nanotubes
    Open this publication in new window or tab >>The correlation between radiative surface defect states and high color rendering index from ZnO nanotubes
    Show others...
    2011 (English)In: Nanoscale Research Letters, ISSN 1931-7573, E-ISSN 1556-276X, Vol. 6, no 513Article in journal (Refereed) Published
    Abstract [en]

    Combined surface, structural and opto-electrical investigations are drawn from the chemically fashioned ZnO nanotubes and its heterostructure with p-GaN film. A strong correlation has been found between the formation of radiative surface defect states in the nanotubes and the pure cool white light possessing averaged eight color rendering index value of 96 with appropriate color temperature. Highly important deep-red color index value has been realized andgt; 95 which has the capability to render and reproduce natural and vivid colors accurately. Diverse types of deep defect states and their relative contribution to the corresponding wavelengths in the broad emission band is suggested.

    Place, publisher, year, edition, pages
    SpringerOpen, 2011
    Keywords
    ZnO nanotubes, ZnO/GaN heterostructure, radiative surface defects, color rendering index, R9 color indexed
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-72037 (URN)10.1186/1556-276X-6-513 (DOI)000296257300001 ()
    Available from: 2011-11-11 Created: 2011-11-11 Last updated: 2017-12-08
    5. Biomimetically Influenced Synthesis of ZnO Dahlia-Flower Shaped Nanoarchitectures
    Open this publication in new window or tab >>Biomimetically Influenced Synthesis of ZnO Dahlia-Flower Shaped Nanoarchitectures
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Three dimensional ZnO dahlia-flower nanoarchitectures have been engineered at room temperature relying on natural oxidation based aqueous chemical synthetic approach. Glycine abetted multicomponent isotropic morphology has been synthesized through the conglomeration of thin nanopetals as building blocks with highly large surface area to volume ratio. Multi-oriented ZnO crystal structure has been achieved by stabilizing its polar surfaces through the adsorption of reactive hydroxyl and amide functions of glycine, exemplifying good corroboration towards x-rays diffraction and Fourier transform infrared ratiocinations.

    Keywords
    Zinc Oxide, Glycine, Nanoflowers, FTIR, Aqueous Chemical Synthetic Technique
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-80632 (URN)
    Available from: 2012-08-28 Created: 2012-08-28 Last updated: 2014-01-15Bibliographically approved
    6. Miniaturization of White Light Emitting Diode on the Borosilicate Glass Pipette
    Open this publication in new window or tab >>Miniaturization of White Light Emitting Diode on the Borosilicate Glass Pipette
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    We present the miniaturization of the white light emitting diode on the borosilicate glass pipette’s tip with the diameter of ~700 nm. Zinc oxide nanowires with the average diameter and length of ~80 nm and ~1.5 μm, respectively, have been chemically synthesized and characterized to investigate the surface morphology, chemical composition and the crystalline nature of the nanoscale structure. The emission capabilities and the color qualities of the broad band emission spectrum from the heterostructure nanodevice have been investigated from electroluminescence measurements and color rendering index calculations.

    Keywords
    Zinc Oxide, White light emitting diodes, Schottky diode, Transmission Electron Microscopy, Color Rendering Index
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-80631 (URN)
    Available from: 2012-08-28 Created: 2012-08-28 Last updated: 2014-01-15Bibliographically approved
  • 10.
    Jamil Rana, Sadaf
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Israr-Qadir, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Biomimetically Influenced Synthesis of ZnO Dahlia-Flower Shaped NanoarchitecturesManuscript (preprint) (Other academic)
    Abstract [en]

    Three dimensional ZnO dahlia-flower nanoarchitectures have been engineered at room temperature relying on natural oxidation based aqueous chemical synthetic approach. Glycine abetted multicomponent isotropic morphology has been synthesized through the conglomeration of thin nanopetals as building blocks with highly large surface area to volume ratio. Multi-oriented ZnO crystal structure has been achieved by stabilizing its polar surfaces through the adsorption of reactive hydroxyl and amide functions of glycine, exemplifying good corroboration towards x-rays diffraction and Fourier transform infrared ratiocinations.

  • 11.
    Jamil Rana, Sadaf
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Israr-Qadir, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Miniaturization of White Light Emitting Diode on the Borosilicate Glass PipetteManuscript (preprint) (Other academic)
    Abstract [en]

    We present the miniaturization of the white light emitting diode on the borosilicate glass pipette’s tip with the diameter of ~700 nm. Zinc oxide nanowires with the average diameter and length of ~80 nm and ~1.5 μm, respectively, have been chemically synthesized and characterized to investigate the surface morphology, chemical composition and the crystalline nature of the nanoscale structure. The emission capabilities and the color qualities of the broad band emission spectrum from the heterostructure nanodevice have been investigated from electroluminescence measurements and color rendering index calculations.

  • 12.
    Jamil-Rana, Sadaf
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Israr-Qadir, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Naturally oxidized synthesis of ZnO dahlia-flower nanoarchitecture2014In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 40, no 8, p. 13667-13671Article in journal (Refereed)
    Abstract [en]

    Three dimensional ZnO dahlia-flowers have been engineered at room temperature relying on natural oxidation based aqueous chemical synthetic approach. Glycine abetted multicomponent isotropic morphology has been synthesized through the conglomeration of thin nanopetals as building blocks with highly large surface area to volume ratio. Highly controllable morphology of thin nanopetals is achieved by stabilizing their polar faces through the adsorption of reactive hydroxyl and amide functions of glycine. Fourier transform infrared conclusions also exemplify good corroboration towards the use of organic additives. Moreover, the synthesized ZnO flowers have been utilized to fabricate cholesterol biosensor and biosensing measurements which have been performed over the cholesterol concentration range of 1 x 10(-6) M to 1 x 10(-3) M.

  • 13.
    Qadir Israr, Muhammed
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Rana Sadaf, Jamil
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Asif, Muhammad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Danielsson, B.
    Lund University.
    Potentiometric cholesterol biosensor based on ZnO nanorods chemically grown on Ag wire2010In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 519, no 3, p. 1106-1109Article in journal (Refereed)
    Abstract [en]

    An electrochemical biosensor based on ZnO nanorods for potentiometric cholesterol determination is proposed. Hexagon-shaped ZnO nanorods were directly grown on a silver wire having a diameter of 250 mu m using low temperature aqueous chemical approach that produced ZnO nanorods with a diameter of 125250 nm and a length of similar to 1 mu m. Cholesterol oxidase (ChOx) was immobilized by a physical adsorption method onto ZnO nanorods. The electrochemical response of the ChOx/ZnO/Ag biosensor against a standard reference electrode (Ag/AgCl) was investigated as a logarithmic function of the cholesterol concentration (1 x 10(-6)M to 1 x 10(-2)M) showing good linearity with a sensitivity of 35.2 mV per decade and the stable output signal was attained at around 10 s.

  • 14.
    Sadaf, Jamal Rana
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Israr, Muhammad Qadir
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Kishwar, Sultana
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    White Electroluminescence Using ZnO Nanotubes/GaN Heterostructure Light-Emitting Diode2010In: NANOSCALE RESEARCH LETTERS, ISSN 1931-7573, Vol. 5, no 6, p. 957-960Article in journal (Refereed)
    Abstract [en]

    We report the fabrication of heterostructure white light-emitting diode (LED) comprised of n-ZnO nanotubes (NTs) aqueous chemically synthesized on p-GaN substrate. Room temperature electroluminescence (EL) of the LED demonstrates strong broadband white emission spectrum consisting of predominating peak centred at 560 nm and relatively weak violet-blue emission peak at 450 nm under forward bias. The broadband EL emission covering the whole visible spectrum has been attributed to the large surface area and high surface states of ZnO NTs produced during the etching process. In addition, comparison of the EL emission colour quality shows that ZnO nanotubes have much better quality than that of the ZnO nanorods. The colour-rendering index of the white light obtained from the nanotubes was 87, while the nanorods-based LED emit yellowish colour.

  • 15.
    Willander, Magnus
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Fakhar-e-Alam, M.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Sultana, Kishwar
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Ali, Syed M. Usman
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Asif, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Applications of Zinc Oxide Nanowires for Bio-photonics and Bio-electronics2011In: Proceedings of SPIE Volume 7940 / [ed] Ferechteh Hosseini Teherani, David C. Look, David J. Rogers, Bellingham, Washington, USA: SPIE - International Society for Optical Engineering, 2011Conference paper (Other academic)
    Abstract [en]

    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.

  • 16.
    Willander, Magnus
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Sadaf, Jamil Rana
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Qadir, Muhammad Israr
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zaman, Saima
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zainelabdin, Ahmed
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Bano, Nargis
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain, Ijaz
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Luminescence from Zinc Oxide Nanostructures and Polymers and their Hybrid Devices2010In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 3, no 4, p. 2643-2667Article, review/survey (Refereed)
    Abstract [en]

    Zinc oxide (ZnO) is a strong luminescent material, as are several polymers. These two materials have distinct drawbacks and advantages, and they can be combined to form nanostructures with many important applications, e. g., large-area white lighting. This paper discusses the origin of visible emission centers in ZnO nanorods grown with different approaches. White light emitting diodes (LEDs) were fabricated by combining n-ZnO nanorods and hollow nanotubes with different p-type materials to form heterojunctions. The p-type component of the hybrids includes p-SiC, p-GaN, and polymers. We conclude by analyzing the electroluminescence of the different light emitting diodes we fabricated. The observed optical, electrical, and electro-optical characteristics of these LEDs are discussed with an emphasis on the deep level centers that cause the emission.

  • 17.
    Willander, Magnus
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zaman, Siama
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zainelabdin, Ahmed
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Amin, Gul
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Jamil Rana, Sadaf
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Israr Qadir, Muhammad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Bano, Nargis
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain, I
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Alvi, Naveed ul Hassan
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Intrinsic White Light Emission from Zinc Oxide Nanorods Heterojunctions on Large Area Substrates2011In: Proceedings of SPIE Volume 7940 / [ed] Ferechteh Hosseini Teherani, David C. Look, David J. Rogers, Bellingham, Washington, USA: SPIE - International Society for Optical Engineering, 2011Conference paper (Other academic)
    Abstract [en]

    Zinc oxide (ZnO) and especially in the nanostructure form is currently being intensively investigated world wide for the possibility of developing different new photonic devices. We will here present our recent findings on the controlled low temperature chemical growth of ZnO nanorods (NRs) on different large area substrates. Many different heterojunctions of ZnO NRs and p-substrates including those of crystalline e. g. p-GaN, p-SiC or amorphous nature e. g. p-polymer coated plastic and p-polymer coated paper will be shown. Moreover, the effect of the p-electrode of these heterojunctions on tuning the emitted wavelength and changing the light quality will be discussed. An example using ZnO NR/p-GaN will be shown and the electrical and electro-optical characteristics will be analyzed. For these heterojunctions the effect of post growth annealing and its effect on the electroluminescence (EL) spectrum will be shown. Finally, intrinsic white light emitting diodes based on ZnO NRs on foldable and disposable amorphous substrates (plastic and paper) will also be presented.

  • 18.
    Willander, Magnus
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Qadir, Muhammad Israr
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Rana, Sadaf Jamil
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Progress on one-dimensional zinc oxide nanomaterials based photonic devices2012In: Nanophotonics, ISSN 2192-8606, Vol. 1, no 1, p. 99-115Article in journal (Refereed)
    Abstract [en]

    One-dimensional nanostructures hold the most attractive and excellent physiochemical characteristics which exhibit the paramount influence on the fundamental and technological nanoelectronic as well as nanophotonic applications. In this review article, we present a detailed introduction to the diverse synthetic procedures which can be utilized for the fabrication of single-, planar- and three-dimensional ZnO nanostructures. More specifically, a thorough discussion regarding luminescence characteristics of the one-dimensional ZnO nanostructures is presented for ultraviolet and visible regions. We summarize the room temperature spontaneous emission and stimulated emission along with the interaction of the incident beam with material cavity to produce resonant optical modes and low-temperature time resolved photoluminescence studies. The most recent published results on the white light emitting diodes fabricated with the combination of ZnO nanotubes with p-GaN and ZnO nanorods with p-organic polymers on glass and disposable paper are discussed. Additionally, the significant results on optically and electrically pumped lasers are discussed; along with an overview on the future of ZnO nanostructures based photonic devices.

  • 19.
    Yang, Li Li
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Zhao, Qingxiang
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Israr, Muhammad Qadir
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Sadaf, Jamil Rana
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Yang, J. H.
    Institute of Condensed State Physics, Jilin Normal University, Siping, 136000, People's Republic of China.
    Indirect optical transition due to surface band bending in ZnO nanotubes2010In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 108, no 10Article in journal (Refereed)
    Abstract [en]

    ZnO nanotubes (ZNTs) have been successfully evolved from ZnO nanorods (ZNRs) by a simple chemical etching process. Two peaks located at 382 nm and 384 nm in the UV emission region has been observed in the room temperature photoluminescence (PL) spectrum of ZNTs since the surface band bending in ZNTs induces the coexistence of indirect and direct transitions in their emission process. In addition, a strong enhancement of total luminescence intensity at room temperature in ZNTs has also be observed in comparison with that of ZNRs. Both temperature-dependent PL and time-resolved PL results not only further testify the coexistence of indirect and direct transitions due to the surface band bending, but also reveal that less nonradiative contribution to the emission process in ZNTs finally causes their stronger luminescence intensity.

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