Ethanol sensing behaviour of tin doped zinc oxide/tin oxide composited nanorod arrays on magnesium-aluminium co-doped zinc oxide seeded layer / Ruziana Mohamed

The ethanol sensor device fabrication was carried out using undoped zinc oxide nanorod (ZnO NR) arrays, tin doped zinc oxide nanorod (Sn:ZnO NR) arrays and novel nanostructured tin doped zinc oxide/tin oxide nanorod (Sn: ZnO/SnO2 NR) arrays film. The sensor consists of a thin film nanostructured deposited on the novel seed layer magnesium-aluminium co-doped zinc oxide (MAZO) coated glass using solution immersion technique. The thin film nanostructures were investigated using X-ray diffraction analysis, energy-dispersive X-ray spectroscopy, field emission scanning electron microsopy, atomic force microscopy, photoluminescence spectrometry, ultraviolet-visible-near-infrared spectrometry, thickness profilometry and two-probe current-voltage measurement system. The sensor performance was analysed based on the change in electrical conductivity upon gas adsorption when ethanol gas was exposed to nanorod arrays film that act as sensing materials. The growth of ZnO NR arrays film was influenced by many factors. In this study, some parameters have been done for ethanol sensor application such as doping process (undoped, single doped and co-doped ZnO seed layer), the variation of coating seed layers (one to nine coating layers), the effect of ZnO NR arrays growth on variation coating layers (one to nine coating layers), the effect of ZnO NR arrays growth at different immersion time (15-90 min), the effect of doping process for ZnO NR arrays (undoped and Sn doped) and the effect of pH of SnO2 solution to the growth of Sn:ZnO/SnO2 NR arrays. The conductometric sensor system was set up to study the sensing sensitivity, response and recovery time and selectivity properties towards ethanol gas. The sensor response for Sn:ZnO/SnO2 NR arrays was 20. It was observed that the Sn:ZnO/SnO2 NR arrays film showed the highest response to the presence of ethanol gas compared ZnO and Sn: ZnO NR arrays. The Sn:ZnO/SnO2 NR arrays showed the shorter of response and recovery time which was around 81 and 63 s, respectively. The sensing sensitivity of Sn:ZnO/SnO2 NR arrays prepared at pH 5.5 of SnO2 solution was increased from 2.4 to 5.2 with an increase of ethanol concentration range 60 to 300 ppm. The Sn:ZnO/SnO2 NR arrays prepared at pH 5.5 of SnO2 solution also showed the increasing of sensing sensitivity value range 2.5 to 8.0 when the working temperature is increased from 60 to 140°C. It also was observed that the Sn:ZnO/SnO2 NR arrays have good selectivity properties towards ehanol vapor as compared to acetone and propanol vapor

Ethanol sensing behaviour of tin doped zinc oxide/tin oxide composited nanorod arrays on magnesium-aluminium codoped zinc oxide seeded layer / Ruziana Mohamed

The ethanol sensor device fabrication was carried out using undoped zinc oxide nanorod (ZnO NR) arrays, tin doped zinc oxide nanorod (Sn:ZnO NR) arrays and novel nanostructured tin doped zinc oxide/ tin oxide nanorod (Sn: ZnO/Sn02 NR) arrays film. The sensor consists of a thin film nanostructured deposited on the novel seed layer magnesiumaluminium co-doped zinc oxide (MAZO) coated glass using solution immersion technique. The thin film nanostructures were investigated using X-ray diffraction analysis, energy-dispersive X-ray spectroscopy, field emission scanning electron microsopy, atomic force microscopy, photoluminescence spectrometry, ultraviolet-visible-near-infrared spectrometry, thickness profilometry and two-probe current-voltage measurement system. The sensor performance was analysed based on the change in electrical conductivity upon gas adsorption when ethanol gas was exposed to nanorod arrays film that act as sensing materials. The growth of ZnO NR arrays film was influenced by many factors. In this study, some parameters have been done for ethanol sensor application such as doping process (undoped, single doped and co-doped ZnO seed layer), the variation of coating seed layers (one to nine coating layers), the effect of ZnO NR arrays growth on variation coating layers (one to nine coating layers), the effect of ZnO NR arrays growth at different immersion time (15-90 min), the effect of doping process for ZnO NR arrays (undoped and Sn doped) and the effect of pH of Sn02 solution to the growth of Sn:ZnO/Sn02 NR arrays. The conductometric sensor system was set up to study the sensing sensitivity, response and recovery time and selectivity properties towards ethanol gas. The sensor response for Sn:ZnO/Sn02 NR arrays was 20. It was observed that the Sn:ZnO/ Sn02 NR arrays film showed the highest response to the presence of ethanol gas compared ZnO and Sn: ZnO NR arrays. The Sn:ZnO/Sn02 NR arrays showed the shorter of response and recovery time which was around 81 and 63 s, respectively. The sensing sensitivity of Sn:ZnO/ Sn02 NR arrays prepared at pH 5.5 of Sn02 solution was increased from 2.4 to 5.2 with an increase of ethanol concentration range 60 to 300 ppm. The Sn:ZnO/Sn02 NR arrays prepared at pH 5.5 of Sn02 solution also showed the increasing of sensing sensitivity value range 2.5 to 8.0 when the working temperature is increased from 60 to 140°C. It also was observed that the Sn:ZnO/Sn02 NR arrays have good selectivity properties towards ehanol vapor as compared to acetone and propanol vapor

'Locus in Cartesian Plane': menggunakan pendekatan 'hands on'dalam meningkatkan kefahaman murid dalam konsep lokus dalam dua dimensi

Lokus dua dimensi ialah satu lintasan set titik-titik yang mematuhi syarat-syarat tertentu. `Locus in Cartesian Plane? ialah satu bahan bantu mengajar dan bahan bantu murid yang boleh mengaplikasi aktiviti `hands on` murid dalam memahami konsep abstrak Lokus dua dimensi. `Locus in Cartesian Plane? terdiri daripada satah Cartesian berliang pada setiap koordinat, garis nombor beralur, garis nombor berliang, jejari bernombor, segiempat beralur garis lurus berliang ditengah, garis nombor bersenggat butang klip dan marker pen. `Cartesian plane` digunakan sebagai satu satah untuk meletakkan titik dengan ditanda dengan klip butang . Jarak tetap pergerakan objek daripada satu titik atau garisan ditentukan dengan garis nombor samada garis nombor beralur, garis nombor berliang, garis nombor beralur atau jejari bernombor. Marker pen digunakan untuk menada lintasan titik-titik (lokus). Kajian telah dijalankan untuk mengatasi masalah yang dihadapi oleh pelajar matematik kelas 3 Bestari (2013) dalam menjawab soalan yang berkaitan masalah lokus. Masalah yang dihadapi pelajar ialah untuk memahami dan melukis lokus mengikut syarat-syarat tertentu dan menentukan persilangan dua lokus. Selepas ujian pos dijalankan, keputusan ujian pos telah menunjukkan peningkatan prestasi pelajar meningkat daripada markah purata 6% kepada kepada 75% Penggunaan Kaedah `Locus in Cartesian Plane? dapat meningkatkan kemahiran menguasai topik Lokus Dalam Dua Dimensi

Characterizations of MoS2 nanosphere fabricated using vacuum thermal evaporation at steady and rapid heating

Two-dimensional MoS2 has been speculated to be the best material to replace graphene due to its peculiar structural-electronic properties. The MoS2 with size smaller than its exciton Bohr radius (ca. 1.61 nm) would favor multi exciton generation upon absorption of photon with sufficient energy, Ephoton ≫ Egap (1.89 eV); which would increase the efficiency of an excitonic solar cell greater than 60%. Despite promising properties of the MoS2, however an excitonic solar cell with high efficiency is yet to be exhibited. In this work, the MoS2 thin films were fabricated using vacuum thermal evaporation technique and characterized. Four objectives have been outlined i.e., to study the effect of heating rate (steady, and rapid) on the (i) morphology, (ii) size, (iii) optoelectronic and (iv) crystal properties of the fabricated thin films. The MoS2 precursor was heated at the rate 2.027 A/s (steady), and 18.75 A/s (rapid), 1.5 × 10−3 Torr, 1.48 A, and 4.58 V. The deposited films later were characterized using Field Emission Scanning Electron Microscope with Energy Dispersive X-ray attachment, photoluminescence spectrometer, UV–vis-NIR spectrometer, and X-ray Diffractometer. The fabricated thin films exhibited nanosphere morphology with different size distributions i.e., wide (steady heating), and narrow (rapid heating). Two hypotheses were made based on the optoelectronic properties i.e., the basic building block of the MoS2 thin film fabricated under steady heating is (i) experiencing stronger quantum confinement effect, and (ii) dominated by nanocrystals which are smaller than that of the rapid heating. Similar energy loss could be expected in both MoS2 thin films i.e., ca. 0.15 to 0.17 eV, indicating the existence of shallow trap states. The MoS2 thin films were dominated by (0 0 2), (0 0 4), and (1 0 6) crystal planes. Therefore, the vacuum thermal evaporation technique would offer materials with unique size, crystal arrangement, and optoelectronic properties upon change of heating rate

Heterogeneous SnO2/ZnO nanoparticulate film: Facile synthesis and humidity sensing capability

Highly sensitive and extremely thin tin oxide/zinc oxide (SnO2/ZnO) heterojunction films were prepared via a two-step solution-based method for humidity-sensing application. The average diameters of the ZnO and SnO2 nanoparticles were 26 and 6 nm, respectively. The deposition of SnO2 for 3 min reduced film resistance from 6.74 MΩ to 0.40 MΩ. Remarkably, the humidity-sensing performance of the heterojunction sensors was critically dependent on deposition time, and sensors subjected to 3 min deposition exhibited the highest sensitivity (90.56) to humidity, which was significantly higher than that of bare ZnO. This study indicates that the use of SnO2/ZnO heterojunction has a great potential in humidity sensing applications

Structural and Electrochemical Behaviors of ZnO Structure: Effect of Different Zinc Precursor Molarity

This research synthesised zinc oxide (ZnO) structure by a hydrothermal method. ZnO samples were prepared using different molarities of zinc (Zn) precursor, ranging from 0.10 to 0.16 M. Structural and morphological properties were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD patterns show that all samples are prominently grown along the three diffraction peaks at (001), (002) and (101) planes. The ZnO sample with 0.16 M Zn precursor has the highest peak orientation along the (002) plane. The average crystallite sizes for the ZnO structure with 0.10, 0.12, 0.14 and 0.16 M precursor are 48, 51, 49 and 31 nm, respectively. ZnO sample prepared at 0.16 M has the smallest crystallite size and the lowest tensile strain. The SEM images show that the ZnO samples are randomly oriented with average diameters of 209, 325, 295 and 348 nm when using 0.10, 0.12, 0.14 and 0.16 M of the precursor, respectively. The electrochemical behaviour of the ZnO structure was determined through cyclic voltammetry (CV) measurement. In the CV curve, the calculated specific capacitance for the ZnO sample prepared at 0.16 M has the highest value of 3.87 Fg−1. The ZnO sample prepared at 0.10 M has the lowest specific capacitance value of 2.11 Fg−1. Therefore, changing the molarity of the Zn precursor could change the structural and electrochemical properties. ZnO sample prepared with 0.16 M of the precursor provides the optimal result

Structural and Electrochemical Behaviors of ZnO Structure: Effect of Different Zinc Precursor Molarity

This research synthesised zinc oxide (ZnO) structure by a hydrothermal method. ZnO samples were prepared using different molarities of zinc (Zn) precursor, ranging from 0.10 to 0.16 M. Structural and morphological properties were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD patterns show that all samples are prominently grown along the three diffraction peaks at (001), (002) and (101) planes. The ZnO sample with 0.16 M Zn precursor has the highest peak orientation along the (002) plane. The average crystallite sizes for the ZnO structure with 0.10, 0.12, 0.14 and 0.16 M precursor are 48, 51, 49 and 31 nm, respectively. ZnO sample prepared at 0.16 M has the smallest crystallite size and the lowest tensile strain. The SEM images show that the ZnO samples are randomly oriented with average diameters of 209, 325, 295 and 348 nm when using 0.10, 0.12, 0.14 and 0.16 M of the precursor, respectively. The electrochemical behaviour of the ZnO structure was determined through cyclic voltammetry (CV) measurement. In the CV curve, the calculated specific capacitance for the ZnO sample prepared at 0.16 M has the highest value of 3.87 Fg−1. The ZnO sample prepared at 0.10 M has the lowest specific capacitance value of 2.11 Fg−1. Therefore, changing the molarity of the Zn precursor could change the structural and electrochemical properties. ZnO sample prepared with 0.16 M of the precursor provides the optimal result

Effect of different coating layer on the topography and optical properties of ZnO nanostructured

Magnesium (Mg) and aluminum (Al) co-doped zinc oxide (MAZO) thin films were synthesized on glass substrate by sol-gel spin coating method. MAZO thin films were prepared at different coating layers range from 1 to 9. Atomic Force Microscopy (AFM) was used to investigate the topography of the thin films. According to the AFM results, Root Means Square (RMS) of MAZO thin films was increased from 0.747 to 6.545 nm, with increase of number coating layer from 1 to 9, respectively. The results shown the variation on structural and topography properties of MAZO seed film when it's deposited at different coating layers on glass substrate. The optical properties was analyzed using UV-Vis spectroscopy. The obtained results show that the transmittance spectra was increased as thin films coating layer increases

Development Of UV monitoring system using metal oxide based sensor

The development of ultraviolet (UV) monitoring system using metal oxide-based sensor has been experimented throughout the project. The metal oxide-based sensor used is the fabricated titanium dioxide nanorod arrays. The sensor is a self-powered UV photosensor that can generate a certain amount of voltage when the illumination of UV radiation exists on the surface of the sensor. Furthermore, the fabricated UV photosensor is designed based on photoelectrochemical (PEC) structure. The performance of the sensor has been experimented by manipulating the quantity of the thin film layer deposited on the surface of the sensor that is used as spacer and applying two different electrolytes that is the solution of salt water (Na2SO4) and mineral water in order to observe the generated output voltage with respect to the distance of UV source to the TiO2 UV photo sensor. Moreover, an Arduino board has been used for monitoring the amount of voltage generated from the photo sensor. The TiO2 UV photo sensor generated the voltage up to 0.3V with standard UV lamp that produces UV radiation wavelength of 365-400nm for a single layer of thin film, electrolytes of Na2SO4 and 5 cm distance of UV lamp from the sensor. Further experiments offer some beneficial results with respect to its properties, that leads to the basis of theoretical and experimental for better understanding of fundamental physics and extensive applications of titanium dioxide (TiO2) related structure

Effect of co-doping process on topography, optical and electrical properties of ZnO nanostructured

We investigated of Undoped ZnO and Magnesium (Mg)-Aluminium (Al) co-doped Zinc Oxide (MAZO) nanostructured films were prepared by sol gel spin coating technique. The surface topography was analyzed using Atomic Force Microscopy (AFM). Based on the AFM results, Root Mean Square (RMS) of MAZO films have rougher surface compared to pure ZnO films. The optical and electrical properties of thin film samples were characterized using Uv-Vis spectroscopy and two point probes, current-voltage (I-V) measurements. The transmittance spectra for both thin samples was above 80% in the visible wavelength. The MAZO film shows the highest conductivity compared to pure ZnO films. This result indicates that the improvement of carrier mobility throughout doping process and possibly contribute by extra ion charge