Growth Of ZnO Nanorods Using Hydrothermal And Modified Chemical Bath Deposition For Device Applications

Zink oksida (ZnO) adalah semikonduktor jurang jalur lebar yang berpotensi dalam aplikasi peranti elektronik dan peranti optoelektronik berkecekapan tinggi. Kajian ini mengandungi dua objektif Zinc oxide (ZnO) is a promising wide band gap semiconductor with applications in high efficiency electronic and optoelectronic devices. The present study follows two objective

Brief Overview on the Fabrication of Light-Emitting Diode (LED) Device via High and Low-Cost Techniques

Why wight LEDs? With 20% of the world's electricity used for lighting, it's been calculated that optimal use of White LED lighting could reduce this to 4%. The use of a White LED will reduce the release of CO2 into the atmosphere by a significant amount. White LEDs are Energy efficient. Long life (A typical White LED lamp can last for 100,000 hours)

Effect of gamma irradiation dose on the structure and pH sensitivity of ITO thin films in extended gate field effect transistor

Even though several studies have demonstrated the use of Indium Tin Oxides (ITO) as an extended gate field effect transistor (EGFET), the effect of different doses of gamma radiation on the intrinsic properties of the ITO films has not been considered. This study investigates the effect of gamma irradiation on the structural, optical, morphological and electrical properties as well as pH sensitivity (as an extended gate field effect transistor) of ITO thin films. ITO thin films with thickness of 400 nm were prepared using a radio frequency sputtering technique. The samples were then subjected to various doses of gamma radiation from a Co-60 radio-isotope (0.5 kGy, 1 kGy, 1.5 kGy, and 2 kGy). The structural and morphological changes as well as transmission and absorption of the thin films were analyzed using X-ray diffraction (XRD), Atomic Force Microscopy (AFM), Field-Emission Scanning Electron Microscope (FESEM) and UV–Vis spectrophotometry, before and after irradiation. The irradiated ITO thin films were then used as an extended gate field effect transistor to determine its ability to improve sensitivity as pH sensors. The grain size and transmittance in the range 300–900 nm of the ITO films were found to decrease with increasing gamma irradiation dose. In contrast, the uniformity and surface roughness of ITO thin films increased with increasing gamma radiation dose due to the formation of lattice defects. Moreover, the electrical resistance of the thin films increased with increasing dose because of the low current density and high number of surface defects associated with irradiation. The pH sensitivity of the ITO thin films improved after irradiation, possibly due to the concomitant increase in surface roughness with increasing radiation dose. The improvements in the pH sensitivity of ITO thin films after irradiation justify their potential use as pH sensors. Keywords: Indium Tin Oxide, Thin films, Gamma irradiation, Optical band gap, X-ray diffraction, EGFET, pH senso

Near Ultra-Violet Electroluminescence from a ZnO Nanorods/p-GaN Heterojunction Light Emitting Diode

The heterostructure of the n-ZnO nanorod (NRs) arrays grown on the p-GaN layer was formed using lowcost hydrothermal technique in order to fabricate a light emitting diode (LED) device. Morphological, structural and optica l properties of as-prepared sample are described. The LED exhibited room temperature current-voltage (1-V) characteristics confirming a rectifying diode behaviour. The device presents near ultra-violet (UV) color under reverse bias. The electroluminescence (EL) spectrum of color emitting LED composed of intense peaks centered at 378 nm and 367 nm. The electroluminescence mechanism of the heterojunction LED was discussed in terms of band diagram

Growth of n-ZnOnanorods on p-GaN using an Aqueous Solution Method

Wide band gap semiconductors like GaN and ZnO have high electron mobility and wide band gap energy. Zinc oxide (ZnO)nanorod arrays are grown on a seed-layer ZnO/GaN l sapphire substrate using a wet chemical bath deposition method. Chemical solution deposition is a low-temperature and possibly the lowest-cost method of growing ZnOnanorods on a GaN substrate. Field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) measurements were used to examine the morphology, phase growth orientation and the structure of the ZnOnanorods and the GaN thin film. Optical property of the as-grown ZnOnanorodsand the GaN thin film was analyzed by room temperature photoluminescence measurements. The synthesis of vertically well-aligned nZnOnanorods on p-GaN film with large aspect ratio, high optical quality, and high density can be very useful for fabricating nanoelectronic and nano-optical devices

Dependence Of V2O5 Nanorods Propertis On Substrate Type Prepared By Simple Hydrothermal Method

Vanadium pentoxide (V2O5) nanorods were prepared on various substrates by simple hydrothermal method. The structural characterizations of V2O5 nanorods (NRs) have been studied by using X-ray diffraction analysis. The influence of the different substrates on the surface morphology of V2O5 NRs was investigated by field emission scanning electron microscopy (FESEM) technique. The results show that the preferred orientation along (001) plane. Raman spectra indicate that glass substrate has optimum results due to the size and number of the nanorods with lower defects. It can be found from the absorbance of the glass substrate increases ccompared with the other substrate

Comparison Study Of Hydrothermally Grown ZnO Nanorods On Untreated Silicon And Black Silicon Substrates

In this paper, the morphological, structural and optical properties of ZnO nanorods grown using the hydrothermal method was studied on two different substrates: untreated silicon and black silicon. Prior to hydrothermal growth, ZnO seed layer was deposited onto the substrates using radio-frequency (RF) sputtering. FESEM imaging was conducted to study the morphology of ZnO nanostructures grown on the substrates. AFM testing was done to determine the surface roughness of both samples. X-Ray diffraction (XRD) and photoluminescence (PL) spectra are obtained to determine the structural and optical properties of ZnO nanostructures. Diffuse reflectance spectra (DRS) was also obtained to determine the ZnO band gap using the Kubelka-Munk theory

ICoFM 2016-58: Influence of Solution Deposition Rate on Properties of V2O5 Thin Films Deposited by spray Pyrolysis Technique

Vanadium oxide (V2O5) thin films were deposited on glass substrates by using a cost-efficient spray pyrolysis technique. The film were grown at 350°C through thermal decomposition VCI3 in deionized water with different solution spray rates. The high resolution X-ray diffraction result revealed the formation of nanocrystalline films having orthorhombic structures with preferential orientation along (101) direction. The spray rate influenced surface morphology and crystallite size of films. The crystallite size was found to increase whereas the micro-strain was decreased by increasing the spray deposition rates. The increase in crystallite size and decrease in the macrostrain resulted in an improvement in the films crystallinity. The UV-Visible spectroscopy analysis indicated that the average transmittance of all films lies in the range 75-80%. The band gap of V2O5 film was decreased from 2.65 to 2.46 eV with increase of the spray deposition rate from 5 ml/min to 10 ml/min

Investigation Of Arabic Gum Optical Properties As Uv-Blue Light Down Conversion For Light Emitting Diode Application

LED’s as energy-efficient lighting is the best way to reduce the cost besides give good brightness. The use of Arabic gum as a remote phosphor for light down conversion. In this study, two experiments were conducted using Gum Arabic Malaysia and Gum Arabic Sudan in different annealing temperature (150°C and 200°C) and different time 20, 40, 60, 80 and 100 minutes and using different mass, 100mg and 150mg. The gum power encapsulated in 0.7ml silicone gel and dried to do remote phosphor using for light conversion. The Gum Arabic from Sudan and Malaysia were measured using HPC-2 light source colorimeter. The measured result show that the gum Arabic has high value in rendering index, CRI if the gum annealed at longer time and at the optimal temperature. The CCT value that show the best result or positive values are below 2500. The gum Arabic with melting process also show improvement in result. The mass of the powder used give high concentration thus the CRI value is nearest to the 80 as references value

Encapsulation Of Ag Nanoparticle-Carbon Composite And Enhancement Of Visible Light ZnO Nanorods Photodiode

In this paper, the effect of encapsulating silver nanoparticles (Ag NPs)- carbon composite onto zinc oxide (ZnO) nanorods (NRs) hydrothermally grown on silicon substrate is characterized and its photodiode performance studied. The composite was dissolved in acetone and drop casted onto ZnO NRs and the samples are baked on a hot plate. FESEM imaging was done and shows the top part of ZnO NRs coated with the composite and EDX testing shows the component are made of carbon as the majority and Ag the minority component. Transmission electron microscopy (TEM) shows the Ag-NPs embedded into the carbon coating. Photoluminescence (PL) spectra shows slight peak broadening of the ZnO main peak at 378 nm. Photodiode measurements shows the encapsulated nanorods has reduced photoresponse to UV light (395 nm) but more responsive to visible light (460 nm) due to creation of new energy states inside the band gap of ZnO