Synthesis and characterizations of ZnO thin films deposited on aluminum metal substrate by sol-gel spin coating technique

In this work, zinc oxide (ZnO) thin films were synthesized on aluminum substrate using sol-gel spin coating technique. The effect of changing in the annealing temperature (from 300 ◦C to 500 ◦C) and the rates of spin (from 1000rpm to 2000rpm) on the structural, optical and piezoelectric properties of the produced films are studied. Zinc acetate dehydrate, absolute ethanol and diethanolamine were used to act as sol gel precursor. Sol gel was coated on glass slide which wrapped by aluminum. The thin film was formed after preheating and annealing. The thin film was characterized by X-ray diffraction (XRD), Photoluminescence Spectroscopy (PL) and Ultraviolet-visible Spectroscopy (UV-Vis). X-ray analysis showed that thin films were preferentially diffracted around 65° which corresponding to (1 1 2) diffraction phase. From the PL results, there was only film with spin speed of 2000 rpm and annealing temperature of 300°C had slightly left wavelength which was 380 nm. Annealing temperature would affect only the intensity of PL wavelength. From the results of UV-Vis, it was observed that when the spin speed was increased at same annealing temperature, the band gap was decreased. When the annealing temperature was increased at same spin speed, the band gap was decreased. This work provides a low cost and environment friendly material for Vibration sensing applications

Job Opportunities in Material(s) Technology

Materials are substances of universe which have properties that make them useful in structures, machines, devices, products, and systems. There are three closely connected areas of study related to materials, namely material(s) technology, materials engineering and materials science. Material(s) technology is a relatively comprehensive discipline that begins with the production of goods from raw materials to processing of materials into the shapes and forms needed for specific applications. Material(s) technologists work with materials such as metals, plastics, rubbers and ceramics. They study how the composition, structure, processing, and application of these materials, are inter-related

Piezoelectric properties of Mg doped ZnO thin film using sol-gel method and spin coating

This reports about the synthesis of Mg doped ZnO thin film using spin-coating techniques through sol-gel method. For studying piezoelectric properties, optical properties and morphology, the prepared Mg doped ZnO thin film samples were characterized using Ultraviolet-Visible Spectroscopy (UV-Vis), Photoluminescence Spectroscopy (PL), X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Ultrasonic Vibrator. The particle size was evaluated using Scherrer’s formula from XRD patterns. The results show the crystallite size decreased with increasing Mg concentrations. The optical properties showed that sample exhibit a blue shift in absorption in UV spectra indicating good optical properties. The morphology of grain size microstructure was observed from FESEM with results the grain size of the samples decreased with increasing Mg doping. The piezoelectric properties were evaluated using ultrasonic vibrator and multimeter to obtain potential difference for each sample. The results obtained that potential difference increase with increasing Mg contents and higher rotation of spin speed was used

Investigation simulation based on bio-energy local area photosensitizer in increasing dye-sensitized solar cells (DSSC) performance

The photosensitizer is an important part of Dye-Sensitized Solar Cells (DSSC). Photosensitizers function like photosynthesis by absorbing sunlight and turning it into energy. Photosensitizers also contribute to the efficiency of improving DSSC performance. This research is a continuation of previous research to find a candidate for natural and environmentally friendly photosensitizer (bio-energy) based local area in Indonesia. The photosensitizer used in this simulation is Tagetes erecta, Nyctanthes arbor-tritis, Brassica rapa Sub. Sp pekinensis, Delonix regia, Lawsonia inermis, Callistemon citrinus, and Daucus Carota. The purpose of this simulation is finding several candidates for bio-energy local area photosensitizer that produce high efficiency by displaying J-V curves and P-V curves. The highest efficiency was produced by photosensitizer Tagetes erecta at 1.5% [Voc 0.6385 Volt, 0.00383 A / cm2 Jsc, FF 0.605 and Pmax 0.00148 Watt], while the lowest efficiency was produced by photosensitizer Callistemon citrinus at 1.1% [Voc 0.6162 Volt, Jsc 0.0032 A / cm2, FF 0.557 and Pmax 0,0011 Watts]. These simulation results perform that one of reason give influence at DSSC performance is the absorption coefficient value in each bio-energy local area photosensitizer. The absorption coefficient also determines how much efficiency is produced and how much the photosensitizer's ability to absorb sunlight

Structural, morphological and shielding effectiveness properties of Yttrium Iron Garnet/Epoxy composites at X-Band frequency prepared via solid state reaction method

The fast progression of microwave absorption technology has caused electromagnetic interference (EMI) or electromagnetic pollution into a worrying situation. Aside from causing adverse effects on industrial apparatus, EM pollution also carries a threat to human health as well. This problem can be prevented by applying Yttrium Iron Garnet (YIG) from Yttrium (III) oxide, Y2O3 and Iron (II) oxide, Fe2O3 as EM shielding material to lessen the EM pollution and interferences. The YIG samples were prepared using a solid-state reaction method and sintered at 900 °C to obtain a single phase of garnet. An epoxy resin was used as a matrix and mixed with YIG with 0 wt%, 5 wt% and 20 wt% compositions of the fillers. The stretching vibrations of the functional groups were analyzed using Fourier Transform Infrared (FTIR). The X-Ray Diffraction (XRD) analysis at a diffraction angle of 10° to 80° confirmed the presence of YIG phase at 900 °C with the average crystallite size was 49.28 nm calculated using Scherrer calculator in X’pert Highscore software. The morphology was determined by Field Emission Scanning Electron Microscope (FESEM) where it is smoother and more homogeneous embedded in the polymer matrix as the composition increases. A Vector Network Analyzer (VNA) was used to measure the shielding effectiveness and the introduction of the sample with the composition of 20 wt% YIG as the filler showed the increment of shielding effectiveness with 1.91 dB which is 4 times higher compared to pure epoxy at the X-band frequency. The results show that the structure and properties of filler materials strongly influence the shielding effectiveness of the composite

Structural and dielectric properties of polyurethane palm oil based filled empty fruit bunch

This paper presents the structural and dielectric properties of polyurethane palm oil based filled empty fruit bunch. Polyurethane filled with empty fruit bunch (PU-EFB) composite was prepared through hot press process. The crystal structure of PU-EFB has been studied using X-ray diffraction technique. The effect of EFB filler content on the microwave dielectric properties of the PU-EFB composites was studied in the X-Band frequency region using Vector Network Analyzerat room temperature. A Kraszewski model showed good correspondence with measured dielectric constant of PUEFB composite, especially at the higher loading level

Behavior of MgO Based Ceramics under Electron Irradiation

MgO is one of environment friendly ceramic material under harsh environment such as electron irradiation. Different response of MgO ceramics under the irradiation was reviewed. The response was in the appearance of surface breakdown/flashover on the surface of MgO after a certain time under irradiation exposure. The different response was shown for small addition of CaO, ZrO2and SiO2into high purity of MgO. Addition of CaO resulted in the appearance of flashover could be 30% earlier of that of pure MgO. Moreover, addition of ZrO2 resulted in 70% earlier. On the other hand, small addition of SiO2 revealed that the MgO based ceramics could withstand the appearance of flashover underthe same energetic electron irradiation

Complex Permittivity Determination of Glycerol Using Graphical and Numerical Technique

Dielectric properties of materials are important parameters because these properties are related to other physical properties such as moisture content. The Cole –Cole model has been used successfully to describe the experimental data for the dielectric constant of many materials as a function of frequency. From Cole-Cole model, the value for dielectric constant divided into two, o= low limit frequency dielectric constant and = high limit frequency dielectric constant. Cole-Cole model also can determine the value for relaxation time of the material, This paper describes the dielectric constant and relaxation time determination of glycerol palm oil based using graphical and numerical methods. The value for dielectric constant was measured by glycerol produced using transesterification process of palm oil and measured at the ambient temperature. Cole-Cole model has been used todescribe the experimental data by using graphical and numerical methods. Using both methods, the value of dielectric constant and relaxation time can be determined by the data obtained from the experiment. Then identify the consistency of the dielectric constant and relaxation times obtained from both the methods were discussed. Dielectric measurement has been carried out to obtain experimental data of dielectric constant and relaxation time for glycerol palm oil based. From numerical method, the value for= 4.0, o= 47 and= 1.62 x10-10s. From graphical method, the value for = 4.0, o= 42.5and = 1.80 x10-10s. By comparing the result to previous research, both methods show a good approach to estimate the dielectric constant and relaxation time for glycerol palm oil based sampl

The effect of green body pressure, sintering time and electric current on ZnO crystal growth by electric current heating method

There are three objectives to be achieved in this research which include to synthesis high purity ZnO pellets with different sintering time and green body pressure by using powder metallurgy process, the growth of ZnO crystal on ceramic bar by applying different current when conducting electric current heating (ECH) method and the characterization of ZnO crystal growth. In this research, high purity of ZnO powder is grinded and compressed at 3.5 tons, 4.5 tons and 5.5 tons to fabricate ZnO green pellets. Then, the ZnO green pellets are sintered for 3 hours and 5 hours. Next, the pellets are cut into bars and apply ECH method. The amount of current applied for the crystal growth are 2A and 3A. Finally, the crystal grown on the ZnO ceramic bar is characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Ultraviolet-visible Spectroscopy (UV-Vis) and Photoluminescence Spectroscopy (PL). High purity ceramic pellets are successfully synthesis by powder metallurgy process. By conducting ECH method, crystal are grown on the surface of ceramic bar. Most crystal structure found in ZnO ceramic bar is needle-liked rod structure which is hexagonally formed by many nanorod. The crystal grown in (100) orientation with the crystalline size of from 57.80 nm to 100.31 nm. The band gap energy obtained from UV-Vis were found between 3.2 eV to 3.4 eV which is nearly similar to the theoretical value of 3.37 eV. Lastly, PL emission measurement give the peak that range between 579 nm to 587 nm which indicate that the sample exhibit yellow colour. Among three different pressure applied, 4.5 tons gives the lowest emission energy. It is considered as the critical pressure in the synthesis of ZnO crystal. The intensity of PL is considered inversely proportional to intensity of XRD in [100] direction. Pressing pressure doesn’t show significant effect on the crystal growth of ZnO but current applied during ECH method and sintering time do give effect on UV-Vis absorption spectra and XRD result respectively