scholarly journals Transferable Substrateless GaN LED Chips Produced by Femtosecond Laser Lift-Off for Flexible Sensor Applications

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 891 ◽  
Author(s):  
Nursidik Yulianto ◽  
Steffen Bornemann ◽  
Lars Daul ◽  
Christoph Margenfeld ◽  
Irene Manglano Clavero ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Light Emitting ◽  
Force Microscopy ◽  
Sensor Applications ◽  
Atomic Force ◽  
Lift Off ◽  
Pulse Energies ◽  
Ultrashort Laser

Transferable substrate-less InGaN/GaN light-emitting diode (LED) chips have successfully been fabricated in a laser lift-off (LLO) process employing high power ultrashort laser pulses with a wavelength of 520 nm. The irradiation of the sample was conducted in two sequential steps involving high and low pulse energies from the backside of the sapphire substrate, which led to self-detachment of the GaN stack layer without any additional tape release procedure. To guarantee their optoelectrical function and surface quality, the lifted LED chips were assessed in scanning electron microscopy (SEM) and electroluminescence (EL) measurements. Moreover, surface characterizations were done using atomic force microscopy (AFM) and Auger Electron Spectroscopy (AES).

scholarly journals Analytical model for the depth progress of percussion drilling with ultrashort laser pulses

2021 ◽  
Vol 127 (5) ◽  
Author(s):  
Daniel Holder ◽  
Rudolf Weber ◽  
Thomas Graf ◽  
Volkher Onuseit ◽  
David Brinkmeier ◽  
...  
Keyword(s):  
Analytical Model ◽  
Experimental Validation ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Picosecond Pulses ◽  
Hole Depth ◽  
Laser Percussion Drilling ◽  
Pulse Energies ◽  
Ultrashort Laser ◽  
Percussion Drilling

AbstractA simplified analytical model is presented that predicts the depth progress during and the final hole depth obtained by laser percussion drilling in metals with ultrashort laser pulses. The model is based on the assumption that drilled microholes exhibit a conical shape and that the absorbed fluence linearly increases with the depth of the hole. The depth progress is calculated recursively based on the depth changes induced by the successive pulses. The experimental validation confirms the model and its assumptions for percussion drilling in stainless steel with picosecond pulses and different pulse energies.

Colloidal quantum dot active layer electroluminescence in a solid GaN matrix

2005 ◽  
Vol 891 ◽  
Author(s):  
Jennifer Pagan ◽  
Edward Stokes ◽  
Kinnari Patel ◽  
Casey Burkhart ◽  
Mike Ahrens
Keyword(s):  
Active Layer ◽  
Light Emitting Diode ◽  
Cdse Quantum Dots ◽  
Light Emitting ◽  
Force Microscopy ◽  
Turn On ◽  
Atomic Force ◽  
Transmission Line Method ◽  
Gan Led ◽  
Colloidal Quantum Dot

ABSTRACTIn this paper the preliminary results of incorporating a novel active layer into a GaN light emitting diode (LED) are discussed. Integration of colloidal CdSe quantum dots into a GaN LED active layer is demonstrated. The conductivity of the overgrowth was examined by circular transmission line method (CTLM). Effects on surface roughness due to the active layer incorporation are examined using atomic force microscopy (AFM). LED test devices were fabricated and electroluminescence was demonstrated, the devices exhibit higher turn-on voltages than would be expected for a CdSe active layer.

High Power 330 nm AlInGaN UV LEDs in the High Injection Regime

2003 ◽  
Vol 798 ◽  
Author(s):  
M. Gherasimova ◽  
J. Su ◽  
G. Cui ◽  
J. Han ◽  
H. Peng ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Threading Dislocation ◽  
Light Emitting ◽  
Force Microscopy ◽  
Sapphire Substrates ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dimensional Growth ◽  
Uv Leds

ABSTRACTWe report on the growth and testing of the light emitting diode structures incorporating quaternary AlInGaN active region with an emission wavelength of 330 nm. Small area circular devices were fabricated, yielding the output power of 110 μW measured with a bare-chip configuration in a high current injection regime (8 kA/cm2 for a 20 μm diameter device). Structural properties of the constituent epitaxial layers were evaluated by atomic force microscopy and transmission electron microscopy, resulting in the observation of two-dimensional growth morphologies of AlN and AlGaN, and the estimate of threading dislocation densities in the low 109 cm-2 range in the structures grown on sapphire substrates.

Thin-disk multipass amplifier for ultrashort laser pulses with kilowatt average output power and mJ pulse energies

2014 ◽  
Author(s):  
Jan-Philipp Negel ◽  
Andreas Voss ◽  
Marwan Abdou Ahmed ◽  
Dominik Bauer ◽  
Dirk Sutter ◽  
...  
Keyword(s):  
Output Power ◽  
Average Output Power ◽  
Laser Pulses ◽  
Thin Disk ◽  
Ultrashort Laser Pulses ◽  
Average Output ◽  
Pulse Energies ◽  
Ultrashort Laser ◽  
Multipass Amplifier

Local nanotip arrays sculptured by atomic force microscopy to enhance the light-output efficiency of GaN-based light-emitting diode structures

2014 ◽  
Vol 25 (19) ◽  
pp. 195401 ◽  
Author(s):  
Chun-Ying Huang ◽  
Yung-Chi Yao ◽  
Ya-Ju Lee ◽  
Tai-Yuan Lin ◽  
Wen-Jang Kao ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Light Emitting Diode ◽  
Light Output ◽  
Light Emitting ◽  
Force Microscopy ◽  
Atomic Force ◽  
Output Efficiency

Effect of GaN Surface Treatment on the Morphological and Optoelectronic Response of Violet Light Emitting Diodes

2004 ◽  
Vol 831 ◽  
Author(s):  
Muhammad Jamil ◽  
James R. Grandusky ◽  
Fatemeh Shahedipour-Sandvik
Keyword(s):  
Organic Solvents ◽  
Light Emitting Diode ◽  
Photoemission Spectroscopy ◽  
Light Emitting ◽  
X Ray ◽  
Force Microscopy ◽  
Treatment Processes ◽  
Atomic Force ◽  
Short Period ◽  
High Roughness

ABSTRACTWe report on the study of the effect of various surface chemical treatment processes of n-GaN template layers used for subsequent growth of light emitting diode (LED) structures. The treatment procedure included cleaning in organic solvents, organic solvents followed by 5 minutes of HCl, organic solvents and 5 minutes of HCl followed by 2 minutes and finally 10 minutes of HF treatment. Chemical, optical and electrical properties of the surfaces of GaN and InGaN-based LED structures were systematically investigated by x-ray photoemission spectroscopy (XPS), auger electron spectroscopy (AES), atomic force microscopy (AFM), photoluminescence (PL) and electroluminescence (EL) spectroscopy. GaN layers that were grown on the samples treated with HCl and HF showed dramatically different surfaces having high density of 3D structures with high roughness. As measured by AFM, growth of the LED structure on top of the GaN layer continued the 3D-growth mode. LED structures grown on the HCl and HF treated GaN template layers showed minimal to no PL and EL emission and failed after a short period. We suggest a qualitative model of the growth that could potentially explain the underlying phenomena leading to such pronounced changes in the optoelectronic properties and surface conditions of the LED structures due to the treatment of the initial template layers.

The topography of organic light-emitting diode-component functional layers as studied by atomic force microscopy

2004 ◽  
Vol 14 (4) ◽  
pp. 155-157 ◽  
Author(s):  
Oksana V. Kotova ◽  
Svetlana V. Eliseeva ◽  
Elena V. Perevedentseva ◽  
Tatyana F. Limonova ◽  
Raida A. Baigeldieva ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Organic Light

scholarly journals Development of High Power Green Light Emitting Diode Chips

2005 ◽  
Vol 10 ◽  
Author(s):  
Christian Wetzel ◽  
T. Detchprobhm
Keyword(s):  
Quantum Wells ◽  
Light Emitting Diode ◽  
Green Light ◽  
High Yield ◽  
Production Scale ◽  
Light Emitting ◽  
Force Microscopy ◽  
Atomic Force ◽  
High Emission ◽  
Optimization Schemes

The development of high emission power green light emitting diodes chips using GaInN/GaN multi quantum well heterostructures on sapphire substrate in our group is being reviewed. We analyze the electronic bandstructure in highly polarized GaInN/GaN quantum wells to identify the appropriate device structures. We describe the optimization of the epitaxial growth for highest device performance. Applying several optimization schemes, we find that lateral smoothness and homogeneity of the active region as characterized by atomic force microscopy is a most telling character of high yield, high output power devices emitting near 525 nm. In un-encapsulated epi-up mounted (400 μm)2 die we achieve 2.5 mW at 20 mA at 525 nm. We describe die performance, wafer yield, and process stability, and reproducibility for our production-scale implementation of this green LED die process.

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