scholarly journals Synthesis of Nanostructure InxGa1-xN Bulk Alloys and Thin Films for LED Devices

Photonics ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 44 ◽  
Author(s):  
B. Kashyout ◽  
Fathy ◽  
Gad ◽  
Badr ◽  
A. Bishara
Keyword(s):  
Thin Films ◽  
Glass Substrate ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Vacuum Evaporation ◽  
Alloy Formation ◽  
Thermal Vacuum ◽  
Light Emitting ◽  
Xrd Patterns ◽  
Bulk Alloys

In this study, we investigated an innovative method for the fabrication of nanostructure bulk alloys and thin films of indium gallium nitride (InxGa1-xN) as active, thin films for light-emitting diode (LED) devices using both crystal growth and thermal vacuum evaporation techniques, respectively. These methods resulted in some tangible improvements upon the usual techniques of InxGa1-xN systems. A cheap glass substrate was used for the fabrication of the LED devices instead of sapphire. Indium (In) and Gallium (Ga) metals, and ammonia (NH3) were the precursors for the alloy formation. The alloys were prepared at different growth temperatures with compositions ranging from 0.1≤x≤0.9. InxGa1-xN alloys at 0.1≤x≤0.9 had different crystallinities with respect to X-Ray diffraction (XRD) patterns where the energy bandgap that was measured by photoluminescence (PL) fell in the range between 1.3 and 2.5 eV. The bulk alloys were utilized to deposit the thin films onto the glass substrate using thermal vacuum evaporation (TVE). The XRD thin films that were prepared by TVE showed high crystallinity of cubic and hexagonal structures with high homogeneity. Using TVE, the InxGa1-xN phase separation of 0.1≤x≤0.9 was eliminated and highly detected by XRD and FESEM. Also, the Raman spectroscopy confirmed the structure that was detected by XRD. The FESEM showed a variance in the grain size of both alloys and thin films. The InxGa1-xN LED device with the structure of glass/GaN/n-In0.1Ga0.9N:n/In0.1Ga0.9N/p-In0.1Ga0.9N:Mg was checked by the light emitted by electroluminescence (EL). White light generation is a promising new direction for the fabrication of such devices based on InxGa1-xN LED devices with simple and low-cost techniques.

scholarly journals Crystal Growth of Cubic and Hexagonal GaN Bulk Alloys and Their Thermal-Vacuum-Evaporated Nano-Thin Films

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1240
Author(s):  
Marwa Fathy ◽  
Sara Gad ◽  
Badawi Anis ◽  
Abd El-Hady B. Kashyout
Keyword(s):  
Thin Films ◽  
Crystal Growth ◽  
Light Emitting Diode ◽  
Hexagonal Phase ◽  
Average Diameter ◽  
High Electron ◽  
Thermal Vacuum ◽  
Light Emitting ◽  
Cubic Structure ◽  
Bulk Alloys

In this study, we investigate a novel simple methodology to synthesize gallium nitride nanoparticles (GaN) that could be used as an active layer in light-emitting diode (LED) devices by combining the crystal growth technique with thermal vacuum evaporation. The characterizations of structural and optical properties are carried out with different techniques to investigate the main featured properties of GaN bulk alloys and their thin films. Field emission scanning electron microscopy (FESEM) delivered images in bulk structures that show micro rods with an average diameter of 0.98 µm, while their thin films show regular microspheres with diameter ranging from 0.13 µm to 0.22 µm. X-ray diffraction (XRD) of the bulk crystals reveals a combination of 20% hexagonal and 80% cubic structure, and in thin films, it shows the orientation of the hexagonal phase. For HRTEM, these microspheres are composed of nanoparticles of GaN with diameter of 8–10 nm. For the optical behavior, a band gap of about from 2.33 to 3.1 eV is observed in both cases as alloy and thin film, respectively. This article highlights the fabrication of the major cubic structure of GaN bulk alloy with its thin films of high electron lifetime.

Porphyrin doping of dichloride-bis(5,7-dichloroquinolin-8-olato)tin(IV) complex for electroluminescence

2013 ◽  
Vol 17 (05) ◽  
pp. 351-358 ◽  
Author(s):  
Mohammad Janghouri ◽  
Ezeddin Mohajerani ◽  
Mostafa M. Amini ◽  
Naser Safari
Keyword(s):  
Molecular Orbital ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Energy Levels ◽  
Orbital Energy ◽  
Homogeneous Layer ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Fundamental Structure ◽  
Organic Light

A method for obtaining red emission from an organic-light emitting diode has been developed by dissolving red and yellow dyes in a common solvent and thermally evaporating the mixture in a single furnace. Dichlorido-bis(5,7-dichloroquinolin-8-olato)tin(IV) complex ( Q2SnCl2 , Q = 5,7-dichloro-8-hydroxyquinoline) has been synthesized for using as a fluorescent material in organic light-emitting diodes (OLEDs). The electronic states HOMO (Highest Occupied Molecular Orbital)/LUMO (Lowest Occupied Molecular Orbital) energy levels explored by means of cyclic voltammetry measurements. A device with fundamental structure of ITO/PEDOT:PSS (55nm)/PVK (90nm)/ Q2SnCl2/Al (180nm) was fabricated and its electroluminescence performance at various thicknesses of light emitting layer (LEL) of Q2SnCl2 is reported. By following this step, an optimal thickness for the doping effect was also identified and explained. Finally a device with fundamental structure of ITO/PEDOT:PSS (55nm)/PVK (90nm)/meso-tetraphenylporphyrin (TPP): Q2SnCl2 (75nm)/ Al (180nm) was fabricated and its electroluminescence performance at various concentrations of dye has been investigated. It is shown that this new method is promising candidate for fabrication of low cost OLEDs at more homogeneous layer.

Low Cost Cooling Device for High Power LED Lamps

2020 ◽  
Author(s):  
Pamela Martinez-Vega ◽  
Araceli Lopez-Badillo ◽  
J. Luis Luviano-Ortiz ◽  
Abel Hernandez-Guerrero ◽  
Jaime G. Cervantes
Keyword(s):  
Reference Model ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Cost Effective ◽  
Heat Sinks ◽  
Modern World ◽  
Type Model ◽  
Light Emitting

Abstract The modern world progressively demands more energy; according to forecasts energy consumption will grow at an average annual rate of 3 percent. Therefore, it is necessary to purchase products or devices that are efficient and environmentally friendly. Technology in LED (Light Emitting Diode) lighting is presented as an alternative to energy saving, since LEDs have proven to be extremely efficient, have a long service life and their cost-effective ratio is very good. However, the heat emitted by the LED chip must be dissipated effectively, since the overheating of the chip reduces the efficiency and lifetime of the lamp. Therefore, heat sinks that are reliable, efficient and inexpensive should be designed and built. The present work proposes new designs for heat sinks in LED lamps, some of the models in the design of the fins refer to the Fibonacci series. The models proposed in the present work that have a significant advantage are the Type 1E Model (5.2% mass savings and better thermal efficiency of 8.33%), GR Type 1 Model (3.12% lighter and 3.33% more efficient) and the GRL Type Model (4. 51% mass savings and 5.55% thermally more efficient) compared to the Type 2 Reference Model proposed by Jang et al. [12].

Surface, interface and electronic properties of F8:F8BT polymeric thin films used for organic light-emitting diode applications

2018 ◽  
Vol 67 (6) ◽  
pp. 691-699 ◽  
Author(s):  
Bruno GAL Borges ◽  
Amanda G Veiga ◽  
Maria Gioti ◽  
Argiris Laskarakis ◽  
Lazaros Tzounis ◽  
...  
Keyword(s):  
Thin Films ◽  
Electronic Properties ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Polymeric Thin Films ◽  
Organic Light Emitting Diode ◽  
Organic Light

scholarly journals Preparation of Organic Light-Emitting Diode Using Coal Tar Pitch, a Low-Cost Material, for Printable Devices

PLoS ONE ◽  
2013 ◽  
Vol 8 (5) ◽  
pp. e62903 ◽  
Author(s):  
Miki Yamaoka ◽  
Shun-suke Asami ◽  
Nayuta Funaki ◽  
Sho Kimura ◽  
Liao Yingjie ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Low Cost ◽  
Coal Tar ◽  
Coal Tar Pitch ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light

1.331μm Narrow-Bandwidth Light Source Based on Polymer Micro-Blazed Grating

2008 ◽  
Author(s):  
Hairong Wang ◽  
Xianni Gao ◽  
Guoliang Sun ◽  
Yulong Zhao ◽  
Zhuangde Jiang
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Diffraction Order ◽  
Blazed Grating ◽  
Light Emitting ◽  
Led Light ◽  
Narrow Bandwidth ◽  
Narrow Width ◽  
The Cost

In order to detect methane (CH4) accurately and reliably, this paper presents a sensor which consists of infrared diode, fixtures, blazed grating, to realize the extremely narrow-bandwidth light at wavelength of 1.331μm. Based on factors such as compatibility with the transmission characteristics of silica fiber and the cost, a LED (light-emitting diode) with center wavelength of 1.3μm is selected. The LED light is modulated as the parallel light beam. As the light is incident in a micro-blazed grating with certain angle, by diffraction and interference, the light will output the maximum light intensity of its diffraction order at 1.331 μm, which just is an absorption peak of CH4. Micro-blazed grating applied here is low cost and easy replication by various ways, which makes extreme narrow width wavelength possible. Simulation and analysis indicate the designed prototype can output 1.331μm with bandwidth from 1.32907μm to 1.332495μm. With the light source basing on light dividing system, more reliable and higher sensitive measurement of the dangerous gases such as methane and carbon monoxide (CO) can be realized.

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