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Article
Publication date: 2 August 2021

Nur Atiqah Hamzah, Mohd Anas Ahmad, Rahil Izzati Mohd Asri, Ezzah Azimah Alias, Mohd Ann Amirul Zulffiqal Md Sahar, Ng Sha Shiong and Zainuriah Hassan

The purpose of this paper is to enhance the efficiency of the LED by introducing three-step magnesium (Mg) doping profile. Attention was paid to the effects of the Mg doping…

Abstract

Purpose

The purpose of this paper is to enhance the efficiency of the LED by introducing three-step magnesium (Mg) doping profile. Attention was paid to the effects of the Mg doping concentration of the first p-GaN layer (i.e. layer close to the active region). Attention was paid to the effects of the Mg doping concentration of the first p-GaN layer (i.e. layer close to the active region).

Design/methodology/approach

Indium gallium nitride (InGaN)–based light-emitting diode (LED) was grown on a 4-inch c-plane patterned sapphire substrate using metal organic chemical vapor deposition. The Cp2Mg flow rates for the second and third p-GaN layers were set at 50 sccm and 325 sccm, respectively. For the first p-GaN layer, the Cp2Mg flow rate varied from 150 sccm to 300 sccm to achieve different Mg dopant concentrations.

Findings

The full width at half maximum (FWHM) for the GaN (102) plane increases with increasing Cp2Mg flow rate. FWHM for the sample with 150, 250 and 300 sccm Cp2Mg flow rates was 233 arcsec, 236 arcsec and 245 arcsec, respectively. This result indicates that the edge and mixed dislocations in the p-GaN layer were increased with increasing Cp2Mg flow rate. Atomic force microscopy (AFM) results reveal that the sample grown with 300 sccm exhibits the highest surface roughness, followed by 150 sccm and 250 sccm. The surface roughness of these samples is 2.40 nm, 2.12 nm and 2.08 nm, respectively. Simultaneously, the photoluminescence (PL) spectrum of the 250 sccm sample shows the highest band edge intensity over the yellow band ratio compared to that of other samples. The light output power measurements found that the sample with 250 sccm exhibits high output power because of sufficient hole injection toward the active region.

Originality/value

Through this study, the three steps of the Mg profile on the p-GaN layer were proposed to show high-efficiency InGaN-based LED. The optimal Mg concentration was studied on the first p-GaN layer (i.e. layer close to active region) to improve the LED performance by varying the Cp2Mg flow rate. This finding was in line with the result of PL and AFM results when the samples with 250 sccm have the highest Mg acceptor and good surface quality of the p-GaN layer. It can be deduced that the first p-GaN layer doping has a significant effect on the crystalline quality, surface roughness and light emission properties of the LED epi structure.

Details

Microelectronics International, vol. 38 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 19 July 2021

Mohd Ann Amirul Zulffiqal Md Sahar, Zainuriah Hassan, Sha Shiong Ng, Way Foong Lim, Khai Shenn Lau, Ezzah Azimah Alias, Mohd Anas Ahmad, Nur Atiqah Hamzah and Rahil Izzati Mohd Asri

The aims of this paper is to study the effects of the V/III ratio of indium gallium nitride (InGaN) quantum wells (QWs) on the structural, optical and electrical properties of…

Abstract

Purpose

The aims of this paper is to study the effects of the V/III ratio of indium gallium nitride (InGaN) quantum wells (QWs) on the structural, optical and electrical properties of near-ultraviolet light-emitting diode (NUV-LED).

Design/methodology/approach

InGaN-based NUV-LED is successfully grown on the c-plane patterned sapphire substrate at atmospheric pressure using metal organic chemical vapor deposition.

Findings

The indium composition and thickness of InGaN QWs increased as the V/III ratio increased from 20871 to 11824, according to high-resolution X-ray diffraction. The V/III ratio was also found to have an important effect on the surface morphology of the InGaN QWs and thus the surface morphology of the subsequent layers. Apart from that, the electroluminescence measurement revealed that the V/III ratio had a major impact on the light output power (LOP) and the emission peak wavelength of the NUV-LED. The LOP increased by up to 53% at 100 mA, and the emission peak wavelength of the NUV-LED changed to a longer wavelength as the V/III ratio decreased from 20871 to 11824.

Originality/value

This study discovered a relation between the V/III ratio and the properties of QWs, which resulted in the LOP enhancement of the NUV-LED. High TMIn flow rates, which produced a low V/III ratio, contribute to the increased LOP of NUV-LED.

Details

Microelectronics International, vol. 38 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 8 July 2021

Ahmad Sauffi Yusof, Zainuriah Hassan, Sidi Ould Saad Hamady, Sha Shiong Ng, Mohd Anas Ahmad, Way Foong Lim, Muhd Azi Che Seliman, Christyves Chevallier and Nicolas Fressengeas

The purpose of this paper is to investigate the effect of growth temperature on the evolution of indium incorporation and the growth process of InGaN/GaN heterostructures.

Abstract

Purpose

The purpose of this paper is to investigate the effect of growth temperature on the evolution of indium incorporation and the growth process of InGaN/GaN heterostructures.

Design/methodology/approach

To examine this effect, the InGaN/GaN heterostructures were grown using Taiyo Nippon Sanso Corporation metal-organic chemical vapor deposition (MOCVD) SR4000-HT system. The InGaN/GaN heterostructures were epitaxially grown on 3.4 µm undoped-GaN (ud-GaN) and GaN nucleation layer, respectively, over a commercial 2” c-plane flat sapphire substrate. The InGaN layers were grown at different temperature settings ranging from 860°C to 820°C in a step of 20°C. The details of structural, surface morphology and optical properties were investigated using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), atomic force microscopy and ultraviolet-visible (UV-Vis) spectrophotometer, respectively.

Findings

InGaN/GaN heterostructure with indium composition up to 10.9% has been successfully grown using the MOCVD technique without any phase separation detected within the sensitivity of the instrument. Indium compositions were estimated through simulation fitting of the XRD curve and calculation of Vegard’s law from UV-Vis measurement. The thickness of the structures was determined using the Swanepoel method and the FE-SEM cross-section image.

Originality/value

This paper report on the effect of MOCVD growth temperature on the growth process of InGaN/GaN heterostructure, which is of interest in solid-state lighting technology, especially in light-emitting diodes and solar cell application.

Details

Microelectronics International, vol. 38 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 10 June 2022

Nur Atiqah Hamzah, Mohd Ann Amirul Zulffiqal Md Sahar, Aik Kwan Tan, Mohd Anas Ahmad, Muhammad Fadhirul Izwan Abdul Malik, Chin Chyi Loo, Wei Sea Chang and Sha Shiong Ng

This study aims to investigate the effects of indium composition on surface morphology and optical properties of indium gallium nitride on gallium nitride (InGaN/GaN…

Abstract

Purpose

This study aims to investigate the effects of indium composition on surface morphology and optical properties of indium gallium nitride on gallium nitride (InGaN/GaN) heterostructures.

Design/methodology/approach

The InGaN/GaN heterostructures were grown on flat sapphire substrates using a metal-organic chemical vapour deposition reactor with a trimethylindium flow rate of 368  sccm. The indium composition of the InGaN epilayers was controlled by applying different substrate temperatures. The surface morphology and topography were observed using field emission scanning electron microscope (F.E.I. Nova NanoSEM 450) and atomic force microscopy (Bruker Dimension Edge) with a scanning area of 10 µm × 10 µm, respectively. The compositional analysis was done by Energy Dispersive X-Ray Analysis. Finally, the ultraviolet-visible (UV-Vis) spectrophotometer (Agilent Technology Cary Series UV-Vis-near-infrared spectrometer) was measured from 200 nm to 1500 nm to investigate the optical properties of the samples.

Findings

The InGaN/GaN thin films have been successfully grown at three different substrate temperatures. The indium composition reduced as the temperature increased. At 760 C, the highest indium composition was obtained, 21.17%. This result was acquired from the simulation fitting of ω−2θ scan on (0002) plane using LEPTOS software by Bruker D8 Discover. The InGaN/GaN shows significantly different surface morphologies and topographies as the indium composition increases. The thickness of InGaN epilayers of the structure was ∼300 nm estimated from the field emission scanning electron microscopy. The energy bandgap of the InGaN was 2.54 eV – 2.79 eV measured by UV-Vis measurements.

Originality/value

It can be seen from this work that changes in substrate temperature can affect the indium composition. From all the results obtained, this work can be helpful towards efficiency improvement in solar cell applications.

Details

Microelectronics International, vol. 40 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 8 July 2021

Muhammad Esmed Alif Samsudin, Yusnizam Yusuf, Norzaini Zainal, Ahmad Shuhaimi Abu Bakar, Christian Zollner, Michael Iza and Steven P. DenBaars

The purpose of this study is to investigate the influence of AlN nucleation thickness in reducing the threading dislocations density in AlN layer grown on sapphire substrate.

Abstract

Purpose

The purpose of this study is to investigate the influence of AlN nucleation thickness in reducing the threading dislocations density in AlN layer grown on sapphire substrate.

Design/methodology/approach

In this work, the effect of the nucleation thickness at 5 nm, 10 nm and 20 nm on reducing the dislocation density in the overgrown AlN layer by metal organic chemical vapor deposition was discussed. The AlN layer without the nucleation layer was also included in this study for comparison.

Findings

By inserting the 10 nm thick nucleation layer, the density of the dislocation in the AlN layer can be as low as 9.0 × 108 cm−2. The surface of the AlN layer with that nucleation layer was smoother than its counterparts.

Originality/value

This manuscript discussed the influence of nucleation thickness and its possible mechanism in reducing dislocations density in the AlN layer on sapphire. The authors believe that the finding will be of interest to the readers of this journal, in particular those who are working on the area of AlN.

Article
Publication date: 7 August 2007

James A. Hunt

This paper seeks to describe automated lamp manufacturing.

1051

Abstract

Purpose

This paper seeks to describe automated lamp manufacturing.

Design/methodology/approach

The paper provides information on the automated manufacture of incandescent, fluorescent and light‐emitting diodes (LEDs).

Findings

The paper finds that the automated manufacture of conventional lamp types is similar, but LEDs require totally different techniques developed from the semiconductor industry.

Originality/value

The paper should be of value in terms of understanding the basics of automated lamp manufacturing, especially with LEDs, as these will be highly important general lighting products to save energy and provide innovation in lighting design in the near future.

Details

Assembly Automation, vol. 27 no. 3
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 4 August 2021

Habeeb Mousa and Kasif Teker

The purpose of this study is to present a systematic investigation of the effect of high temperatures on transport characteristics of nitrogen-doped silicon carbide nanowire-based…

Abstract

Purpose

The purpose of this study is to present a systematic investigation of the effect of high temperatures on transport characteristics of nitrogen-doped silicon carbide nanowire-based field-effect transistor (SiC-NWFET). The 3C-SiC nanowires can endure high-temperature environments due to their wide bandgap, high thermal conductivity and outstanding physical and chemical properties.

Design/methodology/approach

The metal-organic chemical vapor deposition process was used to synthesize in-situ nitrogen-doped SiC nanowires on SiO2/Si substrate. To fabricate the proposed SiC-NWFET device, the dielectrophoresis method was used to integrate the grown nanowires on the surface of pre-patterned electrodes onto the SiO2 layer on a highly doped Si substrate. The transport properties of the fabricated device were evaluated at various temperatures ranging from 25°C to 350°C.

Findings

The SiC-NWFET device demonstrated an increase in conductance (from 0.43 mS to 1.2 mS) after applying a temperature of 150°C, and then a decrease in conductance (from 1.2 mS to 0.3 mS) with increasing the temperature to 350°C. The increase in conductance can be attributed to the thermionic emission and tunneling mechanisms, while the decrease can be attributed to the phonon scattering. Additionally, the device revealed high electron and hole mobilities, as well as very low resistivity values at both room temperature and high temperatures.

Originality/value

High-temperature transport properties (above 300°C) of 3C-SiC nanowires have not been reported yet. The SiC-NWFET demonstrates a high transconductance, high electron and hole mobilities, very low resistivity, as well as good stability at high temperatures. Therefore, this study could offer solutions not only for high-power but also for low-power circuit and sensing applications in high-temperature environments (∼350°C).

Article
Publication date: 17 August 2021

Zulkifli Azman, Nafarizal Nayan, Megat Muhammad Ikhsan Megat Hasnan, Nurafiqah Othman, Anis Suhaili Bakri, Ahmad Shuhaimi Abu Bakar, Mohamad Hafiz Mamat and Mohd Zamri Mohd Yusop

This study aims to investigate the effect of temperature applied at the initial deposition of Aluminium Nitride (AlN) thin-film on a silicon substrate by high-power impulse…

118

Abstract

Purpose

This study aims to investigate the effect of temperature applied at the initial deposition of Aluminium Nitride (AlN) thin-film on a silicon substrate by high-power impulse magnetron sputtering (HiPIMS) technique.

Design/methodology/approach

HiPIMS system was used to deposit AlN thin film at a low output power of 200 W. The ramping temperature was introduced to substrate from room temperature to maximum 100°Cat the initial deposition of thin-film, and the result was compared to thin-film sputtered with no additional heat. For the heat assistance AlN deposition, the substrate was let to cool down to room temperature for the remaining deposition time. The thin-films were characterized by X-ray diffraction (XRD) and atomic force microscope (AFM) while the MIS Schottky diode characteristic investigated through current-voltage response by a two-point probe method.

Findings

The XRD pattern shows significant improvement of the strong peak of the c-axis (002) preferred orientation of the AlN thin-film. The peak was observed narrowed with temperature assisted where FWHM calculated at 0.35° compared to FWHM of AlN thin film deposited at room temperature at around 0.59°. The degree of crystallinity of bulk thin film was improved by 28% with temperature assisted. The AFM images show significant improvement as low surface roughness achieved at around 0.7 nm for temperature assisted sample compares to 3 nm with no heat applied.

Originality/value

The small amount of heat introduced to the substrate has significantly improved the growth of the c-axis AlN thin film, and this method is favorable in the deposition of the high-quality thin film at the low-temperature process.

Details

Microelectronics International, vol. 38 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 5 July 2021

B. Abdallah, F. Nasrallah and W. Tabbky

The purpose of this study was to deposit Bi4Ti3O12 films by electron gun evaporation technique starting from Bi3.25La0.75Ti3O12 as a target without annealing. The films have been…

Abstract

Purpose

The purpose of this study was to deposit Bi4Ti3O12 films by electron gun evaporation technique starting from Bi3.25La0.75Ti3O12 as a target without annealing. The films have been deposited on Si(100), on thin film buffer layer of Pt and glass substrates. X-ray diffraction (XRD) was used to analyze structure of the films, which possesses a good structure with (0010) preferred orientation. Electronic behavior of the samples has been studied.

Design/methodology/approach

The dependence of both the structure and quality of the BLT thin films on different substrates is studied using XRD. The electrical characteristics were determined using capacitance–voltage (C–V) and current–voltage (I–V) measurements at the frequency of 1 MHz. Optical properties of the grown films deposited on glass substrates were characterized by optical transmittance measurements (UV-Vis).

Findings

The XRD analysis approved the crystallographer structure of the prepared Bi4Ti3O12 films. The optical properties of deposited film (transmittance and the band gap value) are extracted by UV-Vis spectrum.

Originality/value

High crystalline quality Bi4Ti3O12 films have been obtained using different substrates at room temperature by means of electron gun deposition. The electrical and ferroelectric properties of thin films were studied using I–V and C–V measurements. The band gap has been found to be about 3.62 eV for the studied film deposited on glass substrate. Electron beam evaporation technique is the most interesting methods, once considering many advantages; such as its stability, reproducibility, high deposition rate and the compositions of the films are controlled.

Details

World Journal of Engineering, vol. 19 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 5 September 2016

Benjamin Tawiah, Liping Zhang, Anli Tian and Shai Shao Fu

The purpose of this paper is to colour aluminium pigment to the highest chroma using SiO2 and organic silane with dichlorotriazine reactive dye and investigate its reaction…

Abstract

Purpose

The purpose of this paper is to colour aluminium pigment to the highest chroma using SiO2 and organic silane with dichlorotriazine reactive dye and investigate its reaction mechanism, chemical stability and thermal properties to improve its applicability in surface coatings.

Design/methodology/approach

Aluminium pigment was encapsulated by the catalysed sol-gel method using SiO2, followed by modification with γ-glycidoxypropyltrimethoxysilane (GPTMS). Purified reactive dye (1-Amino-4-[3-(4,6-dichlorotriazin-2-ylamino)-4-sulfophenylamino]anthraquinone-2-sulfonic acid (X-BR)) was covalently immobilized onto modified SiO2 to obtain coloured aluminium pigment. The reaction mechanism, chemical stability and thermophysical properties were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscope, transmission electron microscope and thermogravimetric analyses (TGA).

Findings

The results showed that X-BR was covalently attached to modified Al/SiO2 with maximum colour grafting of 95 per cent when the dosage of GPTMS and X-BR per weight of modified Al/SiO2 was 25 and 15 per cent, respectively, at pH 8.5 and a temperature of 40°C. The coloured aluminium pigment had good chemical stability with excellent anti-migration properties in many solvents.

Research limitations/implications

The organic silane used required a careful control of pH to ensure maximum colour grafting efficiency meanwhile other silanes with amine groups could also be used effectively with different kinds of colorants besides reactive dyes.

Practical implications

The method used is less cumbersome and provides a simple route to preparing coloured aluminium pigment.

Originality/value

The use of organic-inorganic SiO2/γ- GPTMS with purified reactive dye to covalently colour aluminium pigment to the highest chroma is novel and will help advance the frontiers of knowledge on coloration of aluminium pigments.

Details

Pigment & Resin Technology, vol. 45 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

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