Study Of Glaring Effect From Light Emitting Diodes Via Lens Approach

The purpose of this study was to evaluate the glaring effect from light emitting diode (LED) streetlights using two different brands of lenses. The evaluation was performed by using DIALux 4.1.3 with 70 W LED luminaires by taking into consideration of the same road lighting designs at a pole distance of 35 m and pole height of 10 m on a 7 m wide road. Calculation was performed on a section defined by one pole on one side of the road (single row). The pole height, light overhang and boom length was 10 m, 1 m and 1.5 m, respectively. The light loss factor was 0.85. Tracepro was used to simulate the distribution of light by tracing rays. All mounted luminaries have three zones of light outputs, which were the Backlight, Uplight and Frontlight (Glare) known as BUG rating. The lower the BUG rating was, the fewer light trespass problems the fixture would cause

Effect Of Annealing Temperature On Cerium Oxide Thin Films Grown By Dc Sputtering Method

The cerium thin films were deposited on n-type Si (100) substrate by direct current (DC) sputtering followed by post-annealing at different temperature (400ᵒ C and 600ᵒ C, 800ᵒ C, 1000ᵒ C) in an oxygen ambient. In this study, the effect of annealing temperature on the crystallized CeO2 thin films was characterized by using grazing incidence X-ray diffraction (GIXRD). The surface topology and surface morphology of the CeO2 were analyzed by using atomic force microscopy (AFM) and field emission scanning electron microscope (FESEM). The energy bandgap was calculated from the ultraviolet-visible spectroscopy (UV-Vis) measurement. GIXRD result shows (111) plane has the highest peak intensity, therefore (111) plane was selected as the preferred orientation for CeO2 thin films. AFM results reveal the root-mean-square (RMS) roughness of the CeO2 thin films decreased as annealing temperature increased from 400ᵒC to 1000ᵒC

Effect Of Annealing Temperature On Cerium Oxide Thin Films Grown By DC Sputtering Method

The cerium thin films were deposited on n-type Si (100) substrate by direct current (DC) sputtering followed by post-annealing at different temperature (400ᵒC and 600ᵒC, 800ᵒC, 1000ᵒC) in an oxygen ambient. In this study, the effect of annealing temperature on the crystallized CeO2 thin films was characterized by using grazing incidence X-ray diffraction (GIXRD). The surface topology and surface morphology of the CeO2 were analyzed by using atomic force microscopy (AFM) and field emission scanning electron microscope (FESEM). The energy bandgap was calculated from the ultraviolet-visible spectroscopy (UV-Vis) measurement. GIXRD result shows (111) plane has the highest peak intensity, therefore (111) plane was selected as the preferred orientation for CeO2 thin films. AFM results reveal the root-mean-square (RMS) roughness of the CeO2 thin films decreased as annealing temperature increased from 400ᵒC to 1000ᵒ

A Comparison Study Of ZnO, InZnO, GaZnO And InGaZnO Physical Properties And Optical Bandgap

Comparison between ZnO, InZnO, GaZnO and InGaZnO (IGZO) thin films prepared using spin coating method were studied in detail to find out contribution of In and Ga towards changes in the physical properties. From FESEM, ZnO has revealed an uneven and non-uniform distribution of grains on the film. The addition of In has caused the grains to be more separated and inconsistent in sizes. Ga, on the other hand has transformed the grain to be more hexagonal in shapes and the surface was more packed with grains. AFM analysis has shown dissimilar topographies and surface roughness values to compliment FESEM results. Additionally, optical band gap of ZnO, InZnO, GaZnO and InGaZnO thin films were also calculated and discussed in this study

Effects Of Post-Deposition Annealing Time In Forming Gas Ambient On Y2O3 Films Deposited On Silicon Substrate

The effects of post-deposition annealing (PDA) time (15, 30, and 45 min) at 800˚C in forming gas (95% N2-5% H2) ambient was systematically studied for RF-magnetron sputtered Y2O3 films on n-type Si(100) substrate. X-ray diffraction characterization has revealed the detection of Y2O3 phase oriented in (400), (440), (541), and (543) planes for all of the investigated samples. Atomic force microscopy was utilized to acquire 2-dimensional surface topograpy of Y2O3 films subjected to different PDA time. An increment in rootmean-square roughness was perceived as PDA time was prolonged. In addition, currentvoltage and capacitance-voltage characteristics of the investigated Al/Y2O3/Si-based metaloxide-semiconductor capacitors were also presented in this work

Investigation On Facile Synthesis Of YAG:Ce Nanoceramic Powder Prepared With Microwave Solution Combustion And Application In White Light Emission

Cerium doped yttrium aluminum garnet (YAG:Ce) phosphor was widely used as color converter in white light emitting diode (wLED). Such phosphor was commonly synthesized with high temperature solid-state reaction. However, powder derived from this method exhibited irregular and highly agglomerate particles. A repeated milling process to break the particles will cause additional defects formation, causing the optical properties to deteriorate. In this work, YAG doped with 0.1 mol% of cerium nanoceramic powder has been synthesized with facile mixed-fuel microwave solution combustion synthesis (MSCS). The as-synthesized powder was subjected to a post-annealing treatment to enhance the structural and optical properties. HR-XRD revealed an increased in crystallinity as well as crystallite size for the annealed powder. Moreover, FESEM analysis showed spherical-like nanoparticles morphology. For optical properties, broad yellow emission centered at 534 nm was demonstrated with PL measurement. Finally, the YAG:Ce phosphors was fabricated into wLED and characterized with electroluminescence (EL) measurement to determine the color properties (CIE, CCT and CRI)

Investigation On Facile Synthesis Of YAG:Ce Nanoceramic Powder Prepared With Microwave Solution Combustion And Application In White Light Emission

Cerium doped yttrium aluminum garnet (YAG:Ce) phosphor was widely used as color converter in white light emitting diode (wLED). Such phosphor was commonly synthesized with high temperature solid-state reaction. However, powder derived from this method exhibited irregular and highly agglomerate particles. A repeated milling process to break the particles will cause additional defects formation, causing the optical properties to deteriorate. In this work, YAG doped with 0.1 mol% of cerium nanoceramic powder has been synthesized with facile mixed-fuel microwave solution combustion synthesis (MSCS). The as-synthesized powder was subjected to a post-annealing treatment to enhance the structural and optical properties. HR-XRD revealed an increased in crystallinity as well as crystallite size for the annealed powder. Moreover, FESEM analysis showed spherical-like nanoparticles morphology. For optical properties, broad yellow emission centered at 534 nm was demonstrated with PL measurement. Finally, the YAG:Ce phosphors was fabricated into wLED and characterized with electroluminescence (EL) measurement to determine the color properties (CIE, CCT and CRI)

Influence Of Etching Time On The Porous P-Type Gallium Nitride Using Alternating Current Photo-Assisted Electrochemical Etching Technique

The theoretical and experimental study of porous p-type gallium nitride (GaN) is discussed in this work. Porous p-type GaN was adequately fabricated using alternating current photo-assisted electrochemical etching technique with various etching times (10, 20, 30, and 60 minutes) in mixed hydrofluoric acid and ethanol electrolyte solutions (1:4 volume ratios) under ultraviolet illuminations. The evolution of morphology of non-porous and porous p-type GaN as a function of etching time was imaged using field emission scanning electron microscopy measurement. Surface analysis revealed a sporadic pore size with circular shape was found in porous p-type GaN while smooth and no pores was observed in non-porous p-type GaN sample. Etching for a brief time frame resulted in small pores, and etching for longer times resulted in enormous pores. However, prolonged etching times of 60 minutes would prompt breakdown of porous layer. The average pore diameter and porosity of the investigated samples were estimated from the ImageJ software. Subsequent effort by investigating the structural characteristics of non-porous and porous samples by variety of methods, including high resolution x-ray diffraction and atomic force microscopy. A significant increase in the surface roughness was observed with an increase in the etching time. The discoveries found that the influence of etching duration has indicated noteworthy impacts towards morphological and structural properties of the porous p-type GaN, as supportively revealed through pore size, porosity, and surface roughnes

Morphological And Structural Properties Of Sol-Gel Derived ZnO Thin Films Spin-Coated On Different Substrates

In this work, ZnO thin films were prepared by the low-cost sol-gel method onto six different substrates (glass, ITO coated glass, sapphire (Al2O3), p-Si, p-GaN and polyethylene terephthalate (PET)) to study the effects of these substrates on the morphological and structural properties of the produced films. Zinc acetate dihydrate dissolved in ethanol was used as a precursor while monoethanolamine (C2H7NO) was added to serve as a base and complexing agent. The corresponding ZnO thin films were characterized using Field Emission Scanning Electron Microscopy (FESEM), high resolution X-ray diffraction (XRD) and atomic force microscopy (AFM). Results revealed distinct morphological and structural properties of ZnO thin films deposited on each substrate. The most uniform morphology was identified on glass, owing to the acquisition of the averagely stable grain sizes (58 nm – 61 nm) and thin film thicknesses (280 nm – 325 nm). High resolution XRD analysis showed that the films deposited on glass, ITO, p-Si, and p-GaN were attributed to hexagonal crystallite structures while the films deposited on sapphire and PET substrates exhibited amorphous phases. Amongst the samples, the ZnO thin film deposited on p-Si demonstrated preferred orientation in (002) direction

Influence Of Etching Time On The Porous P-Type Gallium Nitride Using Alternating Current Photo-Assisted Electrochemical Etching Technique

The Theoretical And Experimental Study Of Porous P-Type Gallium Nitride (Gan) Is Discussed In This Work. Porous P-Type Gan Was Adequately Fabricated Using Alternating Current Photo-Assisted Electrochemical Etching Technique With Various Etching Times (10, 20, 30, And 60 Minutes) In Mixed Hydrofluoric Acid And Ethanol Electrolyte Solutions (1:4 Volume Ratios) Under Ultraviolet Illuminations. The Evolution Of Morphology Of Non-Porous And Porous P-Type Gan As A Function Of Etching Time Was Imaged Using Field Emission Scanning Electron Microscopy Measurement. Surface Analysis Revealed A Sporadic Pore Size With Circular Shape Was Found In Porous P-Type Gan While Smooth And No Pores Was Observed In Non-Porous P-Type Gan Sample. Etching For A Brief Time Frame Resulted In Small Pores, And Etching For Longer Times Resulted In Enormous Pores. However, Prolonged Etching Times Of 60 Minutes Would Prompt Breakdown Of Porous Layer. The Average Pore Diameter And Porosity Of The Investigated Samples Were Estimated From The Imagej Software. Subsequent Effort By Investigating The Structural Characteristics Of Non-Porous And Porous Samples By Variety Of Methods, Including High Resolution X-Ray Diffraction And Atomic Force Microscopy. A Significant Increase In The Surface Roughness Was Observed With An Increase In The Etching Time. The Discoveries Found That The Influence Of Etching Duration Has Indicated Noteworthy Impacts Towards Morphological And Structural Properties Of The Porous P-Type Gan, As Supportively Revealed Through Pore Size, Porosity, And Surface Roughness