Studies and Applications of Advanced Laser Scribing for High Brightness LEDs

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 000684-000705
Author(s):  
Irving Chyr ◽  
Cheng Peng ◽  
Ji Wang ◽  
Jonathan Halderman
Keyword(s):  
Electron Microscopy ◽  
Electrical Properties ◽  
Light Output ◽  
Optical And Electrical Properties ◽  
Sidewall Roughness ◽  
High Brightness ◽  
Sapphire Substrates ◽  
Laser Scribing ◽  
Different Types ◽  
Line Texture

The optical and electrical properties of LEDs scribed using both traditional and advanced laser scribing were investigated. Variations in scribe line texture and depth were examined and monitored for both laser types using both optical and electron microscopy. Simulation was conducted and verified by the experimental results on laser scribing depth versus LED light output. The metrology techniques also correlated the sidewall roughness with light output of LED between traditional and advanced laser scribing. Improvements by the advanced laser scribing were demonstrated for different LED designs, such as DBR with metal mirrors. Our study showed that the advanced laser scribing is comparable to the sidewall etching process which is the current industrial standard. Our advanced laser scribing system can process different types of metal mirrors on top of DBR structures in a single tool solution. We also presented our latest results on the emerging new substrates of vertical LEDs on Si and other advanced non-sapphire substrates.

scholarly journals Optical and Electrical Properties of SnO2:F Thin Films Obtained by R.F. Sputtering With Various Targets

1991 ◽  
Vol 14 (3) ◽  
pp. 111-118 ◽  
Author(s):  
C. Geoffroy ◽  
G. Campet ◽  
F. Menil ◽  
J. Portier ◽  
J. Salardenne ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Tin Oxide ◽  
Atomic Ratio ◽  
Optical And Electrical Properties ◽  
Argon Gas ◽  
Glass Substrates ◽  
Different Types ◽  
Spray Technique ◽  
Tin Oxide Films

Tin oxide films were deposited on glass substrates by reactive and non reactive r.f. sputtering using different types of targets corresponding to various Sn/F atomic ratio: hot pressed Sn–SnF2or SnO2–SnF2mixtures, ceramics obtained by casting either an aqueous SnO2–SnF2slurry or a suspension of tin oxide in molten tin fluoride. The samples were prepared in oxygen-argon gas mixtures in which the oxygen concentration was varied from 0 mole % up to 30 mole% depending on the target. The optical and electrical properties of the obtained thin films have been studied and compared to those of the films obtained by spray technique.

Transparent Conducting Zinc Stannate Films Prepared on α-Al2O3 (0001) by MOCVD

2014 ◽  
Vol 893 ◽  
pp. 558-561
Author(s):  
Feng Ji ◽  
Xue Zhang ◽  
Chang Lv ◽  
Zhen Tai Hou
Keyword(s):  
Electrical Properties ◽  
Optical And Electrical Properties ◽  
High Quality ◽  
Zinc Stannate ◽  
Sapphire Substrates ◽  
Transparent Conducting Films ◽  
Transparent Conducting

High quality crystalline zinc-stannate transparent conducting films were successfully prepared on sapphire substrates by MOCVD method. ZnSnO films with the proportions of tin and zinc from 1: 1 to 1:20 were prepared and ZnSnO3films were obtained when the proportion is 1:1. The structural, optical and electrical properties of zinc-stannate films were investigated.

Gan-Based Leds Grown on Cone-Shaped Patterned Sapphire Substrates with Peripheral Air Voids by Lateral Etching

2011 ◽  
Vol 422 ◽  
pp. 542-546
Author(s):  
Nan Ming Lin ◽  
Shih Chang Shei ◽  
Shoou Jinn Chang ◽  
Wei Chih Lai ◽  
Yang Ya Yu ◽  
...  
Keyword(s):  
Output Power ◽  
Light Output ◽  
Patterned Sapphire Substrate ◽  
Air Voids ◽  
Sapphire Substrates ◽  
Flat Substrate ◽  
Laser Scribing ◽  
Mocvd Growth ◽  
One Step ◽  
Patterned Sapphire Substrates

In this study, the authors report that GaN-based LEDs prepared on 1.2μm, 1.4μm, and 1.7μm height of cone-shaped patterned sapphire substrates (CSPSS) with the formation of air voids at GaN/cone-shaped-patterned-sapphire-substrate interface by laser scribing and lateral etching with one-step MOCVD growth. With CSPSS, it can be seen that output powers were all significantly larger than that of LED with flat substrate (FS). Assisted by 20 min lateral etching, it was found that peripheral pyramid-like air-voids were formed on top of each cone of the CSPSS with 1.7μm height and the light output power increased by 13.8%, compared with the result of the CSPSS with 1.2μm height. Furthermore, it was also found that output power of LED prepared on 1.7μm height of CSPSS with 20 min lateral etching was 6.2 and 3.1% larger than those of LEDs prepared on 1.2μm and 1.4μm height of CSPSS with 20 min lateral etching, respectively.

scholarly journals Improving Optical and Electrical Properties of GaN Epitaxial Wafers and Enhancing Luminescent Properties of GaN-Based Light-Emitting-Diode with Excimer Laser Irradiation

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1935
Author(s):  
Yijian Jiang ◽  
Haoqi Tan ◽  
Yan Zhao
Keyword(s):  
Electrical Properties ◽  
Laser Irradiation ◽  
Excimer Laser ◽  
Laser Energy ◽  
Hole Concentration ◽  
Light Output ◽  
Annealing Treatment ◽  
Optical And Electrical Properties ◽  
Excimer Laser Irradiation ◽  
Krf Excimer Laser

The effect of KrF excimer laser irradiation on the optical and electrical properties of epitaxial wafers with a p-GaN surface were investigated at different laser energy densities and pulse numbers. The laser-irradiated samples were annealed in oxygen. The laser irradiation-induced changes in optical and electrical properties of GaN epitaxial wafers were examined using PL, I–V, XPS, SIMS, and Hall effect measurements. Experimental results show that under an appropriate laser-irradiated condition, optical and electrical properties of the samples were improved to different degrees. The samples which were annealed after laser irradiation have better electrical properties such as the hole concentration and sheet resistance than those without annealing. We hypothesize that the pulsed KrF excimer laser irradiation dissociates the Mg–H complexes and annealing treatment allows the hydrogen to diffuse out more completely under the oxygen atmosphere at a proper temperature, by which the crystalline symmetry of GaN is improved. Under appropriate laser conditions and O2-activated annealing, the light output of the laser-irradiated GaN-based LED sample is about 1.44 times that of a conventional LED at 20 mA. It is found that the wall-plug efficiency is 10% higher at 20 mA and the reverse leakage current is 80% lower at 5 V.

Effect of nitridation time on structural, optical and electrical properties of InN films grown on c-sapphire substrates by PAMBE

2017 ◽  
Vol 29 (5) ◽  
pp. 3927-3934
Author(s):  
Kankat Ghosh ◽  
Ritam Sarkar ◽  
Swagata Bhunia ◽  
Apurba Laha
Keyword(s):  
Electrical Properties ◽  
Optical And Electrical Properties ◽  
Sapphire Substrates ◽  
Nitridation Time

Structural, optical, and electrical properties of laser deposited FeTiO3 films on C- and A-cut sapphire substrates

1999 ◽  
Vol 85 (10) ◽  
pp. 7433-7437 ◽  
Author(s):  
Z. Dai ◽  
H. Naramoto ◽  
K. Narumi ◽  
S. Yamamoto ◽  
A. Miyashita
Keyword(s):  
Electrical Properties ◽  
Optical And Electrical Properties ◽  
Sapphire Substrates

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

Scanning electron microscopy of asbestos-containing material where the asbestos fibers are considered locked in a binder

1993 ◽  
Vol 51 ◽  
pp. 472-473
Author(s):  
J. R. Millette ◽  
R. S. Brown
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Protection Agency ◽  
Building Materials ◽  
The United States ◽  
Protection Agency ◽  
Asbestos Fibers ◽  
Different Types ◽  
Binder Material ◽  
Scanning Electron

The United States Environmental Protection Agency (EPA) has labeled as “friable” those building materials that are likely to readily release fibers. Friable materials when dry, can easily be crumbled, pulverized, or reduced to powder using hand pressure. Other asbestos containing building materials (ACBM) where the asbestos fibers are in a matrix of cement or bituminous or resinous binders are considered non-friable. However, when subjected to sanding, grinding, cutting or other forms of abrasion, these non-friable materials are to be treated as friable asbestos material. There has been a hypothesis that all raw asbestos fibers are encapsulated in solvents and binders and are not released as individual fibers if the material is cut or abraded. Examination of a number of different types of non-friable materials under the SEM show that after cutting or abrasion, tuffs or bundles of fibers are evident on the surfaces of the materials. When these tuffs or bundles are examined, they are shown to contain asbestos fibers which are free from binder material. These free fibers may be released into the air upon further cutting or abrasion.

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