scholarly journals Zigzag and Helical AlN Layer Prepared by Glancing Angle Deposition and Its Application as a Buffer Layer in a GaN-Based Light-Emitting Diode

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Lung-Chien Chen ◽  
Ching-Ho Tien ◽  
Liu Xuguang ◽  
Xu Bingshe
Keyword(s):  
Buffer Layer ◽  
Light Emitting Diode ◽  
Three Dimensional ◽  
Light Output ◽  
Glancing Angle Deposition ◽  
Three Dimensional Model ◽  
Light Emitting ◽  
Glancing Angle ◽  
Aln Buffer ◽  
Angle Deposition

This study investigates an aluminum nitride (AlN) nanorod structure sputtered by glancing angle deposition (GLAD) and its application as a buffer layer for GaN-based light-emitting diodes (LEDs) that are fabricated on sapphire substrates. The ray tracing method is adopted with a three-dimensional model in TracePro software. Simulation results indicate that the zigzag AlN nanorod structure is an optimal buffer layer in a GaN-based LED. Furthermore, the light output power of a GaN-based LED with a zigzag AlN nanorod structure improves to as much as 28.6% at a forward current of 20 mA over that of the GaN-based LED with a normal AlN buffer layer.

scholarly journals Enhanced Device Performance of GaInN-Based Green Light-Emitting Diode with Sputtered AlN Buffer Layer

2019 ◽  
Vol 9 (4) ◽  
pp. 788 ◽  
Author(s):  
Seiji Ishimoto ◽  
Dong-Pyo Han ◽  
Kengo Yamamoto ◽  
Ryoya Mano ◽  
Satoshi Kamiyama ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Buffer Layer ◽  
Light Emitting Diode ◽  
Light Output ◽  
Green Light ◽  
Device Performance ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Current Characteristics ◽  
Aln Buffer

In this study, we compared the device performance of GaInN-based green LEDs grown on c-plane sapphire substrates with a conventional low temperature GaN buffer layer to those with a sputtered-AlN buffer layer. The light output power and leakage current characteristics were significantly improved by just replacing the buffer layer with a sputtered-AlN layer. To understand the origin of the improvement in performance, the electrical and optical properties were compared by means of electro-reflectance spectroscopy, I–V curves, electroluminescence spectra, L–I curves, and internal quantum efficiencies. From the analysis of the results, we concluded that the improvement is mainly due to the mitigation of strain and reduction of the piezoelectric field in the multiple quantum wells active region.

scholarly journals Improved Performance of GaN-Based Light-Emitting Diodes Grown on Si (111) Substrates with NH3 Growth Interruption

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 399
Author(s):  
Sang-Jo Kim ◽  
Semi Oh ◽  
Kwang-Jae Lee ◽  
Sohyeon Kim ◽  
Kyoung-Kook Kim
Keyword(s):  
Buffer Layer ◽  
Light Emitting Diodes ◽  
Defect Density ◽  
Strain Relaxation ◽  
Multiple Quantum Well ◽  
Light Output ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Growth Interruption ◽  
Aln Buffer

We demonstrate the highly efficient, GaN-based, multiple-quantum-well light-emitting diodes (LEDs) grown on Si (111) substrates embedded with the AlN buffer layer using NH3 growth interruption. Analysis of the materials by the X-ray diffraction omega scan and transmission electron microscopy revealed a remarkable improvement in the crystalline quality of the GaN layer with the AlN buffer layer using NH3 growth interruption. This improvement originated from the decreased dislocation densities and coalescence-related defects of the GaN layer that arose from the increased Al migration time. The photoluminescence peak positions and Raman spectra indicate that the internal tensile strain of the GaN layer is effectively relaxed without generating cracks. The LEDs embedded with an AlN buffer layer using NH3 growth interruption at 300 mA exhibited 40.9% higher light output power than that of the reference LED embedded with the AlN buffer layer without NH3 growth interruption. These high performances are attributed to an increased radiative recombination rate owing to the low defect density and strain relaxation in the GaN epilayer.

Simulation of 3D Films Deposited by Glancing Angle Deposition Using 3D-Films

2000 ◽  
Vol 616 ◽  
Author(s):  
T. Smy ◽  
D. Vick ◽  
M. J. Brett ◽  
S. K. Dew ◽  
A. T. Wu ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Three Dimensional ◽  
Thin Film Deposition ◽  
Glancing Angle Deposition ◽  
Film Deposition ◽  
Porous Thin Films ◽  
Glancing Angle ◽  
Memory Resources ◽  
Angle Deposition

AbstractA new fully three dimensional (3D) ballistic deposition simulator 3D-FILMS has been developed for the modeling of thin film deposition and structure. The simulator may be implemented using the memory resources available to workstations. In order to illustrate the capabilities of 3D-FILMS, we apply it to the growth of engineered porous thin films produced by the technique of GLancing Angle Deposition (GLAD).

scholarly journals Light-Output Enhancement of GaN-Based Light-Emitting Diodes with Three-Dimensional Backside Reflectors Patterned by Microscale Cone Array

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Huamao Huang ◽  
Jinyong Hu ◽  
Hong Wang
Keyword(s):  
Light Emitting Diode ◽  
Three Dimensional ◽  
Light Output ◽  
Bragg Reflector ◽  
Light Extraction Efficiency ◽  
Distributed Bragg Reflector ◽  
Etching Technique ◽  
Light Emitting ◽  
Triangle Lattice ◽  
Wall Plug Efficiency

Three-dimensional (3D) backside reflector, compared with flat reflectors, can improve the probability of finding the escape cone for reflecting lights and thus enhance the light-extraction efficiency (LEE) for GaN-based light-emitting diode (LED) chips. A triangle-lattice of microscale SiO2cone array followed by a 16-pair Ti3O5/SiO2distributed Bragg reflector (16-DBR) was proposed to be attached on the backside of sapphire substrate, and the light-output enhancement was demonstrated by numerical simulation and experiments. The LED chips with flat reflectors or 3D reflectors were simulated using Monte Carlo ray tracing method. It is shown that the LEE increases as the reflectivity of backside reflector increases, and the light-output can be significantly improved by 3D reflectors compared to flat counterparts. It can also be observed that the LEE decreases as the refractive index of the cone material increases. The 3D 16-DBR patterned by microscale SiO2cone array benefits large enhancement of LEE. This microscale pattern was prepared by standard photolithography and wet-etching technique. Measurement results show that the 3D 16-DBR can provide 12.1% enhancement of wall-plug efficiency, which is consistent with the simulated value of 11.73% for the enhancement of LEE.

scholarly journals Multilayer thin film encapsulation for organic light emitting diodes

RSC Advances ◽  
2014 ◽  
Vol 4 (21) ◽  
pp. 10808-10814 ◽  
Author(s):  
Rakhi Grover ◽  
Ritu Srivastava ◽  
M. N. Kamalasanan ◽  
D. S. Mehta
Keyword(s):  
Thin Film ◽  
Glancing Angle Deposition ◽  
Organic Light Emitting Diodes ◽  
Organic Films ◽  
Light Emitting ◽  
Organic Light ◽  
Glancing Angle ◽  
Alternate Layer ◽  
Angle Deposition ◽  
Thin Film Encapsulation

Thin film encapsulation for OLEDs using alternate layer pairs of organic films and magnesium fluoride thin films deposited by normal and glancing angle deposition methods.

scholarly journals Three-dimensional structural comparison of tantalum glancing angle deposition thin films by FIB-SEM

2019 ◽  
Vol 8 (2) ◽  
pp. 305-315
Author(s):  
Tobias Ott ◽  
Diego Roldán ◽  
Claudia Redenbach ◽  
Katja Schladitz ◽  
Michael Godehardt ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Glancing Angle Deposition ◽  
Infrared Sensors ◽  
Geometric Information ◽  
Tantalum Films ◽  
Glancing Angle ◽  
Nano Rods ◽  
Angle Deposition

Abstract. Thin tantalum films generated by glancing angle deposition serve as functional optical layers, for instance as absorption layers for ultrathin infrared sensors. They consist of nano-rods whose dimensions and distribution influence the optical properties of the thin film. Serial sectioning by a focused ion beam combined with scanning electron microscopy of the slices generates stacks of highly resolved images of this nanostructure. Dedicated image processing reconstructs the spatial structure from this stack such that 3-D image analysis yields geometric information that can be related to the optical performance.

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