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.

scholarly journals Characterisation of InGaN by Photoconductive Atomic Force Microscopy

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1794 ◽  
Author(s):  
Thomas Weatherley ◽  
Fabien Massabuau ◽  
Menno Kappers ◽  
Rachel Oliver
Keyword(s):  
Atomic Force Microscopy ◽  
Cross Sections ◽  
Indium Content ◽  
Light Emitting ◽  
Force Microscopy ◽  
Turn On ◽  
Atomic Force ◽  
Voltage Curve ◽  
Current Voltage Curve ◽  
The Impact

Nanoscale structure has a large effect on the optoelectronic properties of InGaN, a material vital for energy saving technologies such as light emitting diodes. Photoconductive atomic force microscopy (PC-AFM) provides a new way to investigate this effect. In this study, PC-AFM was used to characterise four thick (∼130 nm) In x Ga 1 − x N films with x = 5%, 9%, 12%, and 15%. Lower photocurrent was observed on elevated ridges around defects (such as V-pits) in the films with x ≤ 12 %. Current-voltage curve analysis using the PC-AFM setup showed that this was due to a higher turn-on voltage on these ridges compared to surrounding material. To further understand this phenomenon, V-pit cross sections from the 9% and 15% films were characterised using transmission electron microscopy in combination with energy dispersive X-ray spectroscopy. This identified a subsurface indium-deficient region surrounding the V-pit in the lower indium content film, which was not present in the 15% sample. Although this cannot directly explain the impact of ridges on turn-on voltage, it is likely to be related. Overall, the data presented here demonstrate the potential of PC-AFM in the field of III-nitride semiconductors.

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.

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.

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).

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.

&[mu]-Watt Enhanced Electroluminescent Power of Silicon Nanocrystal Light-Emitting Diodes Made on Nano-Scale Silicon-Tip-Array Substrate

2007 ◽  
Vol 989 ◽  
Author(s):  
Gong-Ru Lin ◽  
Chun-Jung Lin
Keyword(s):  
Light Emitting Diode ◽  
Optical Power ◽  
Oxide Semiconductor ◽  
Si Substrate ◽  
Light Emitting ◽  
Pillar Array ◽  
Turn On ◽  
Air Interface ◽  
Order Of Magnitude ◽  
Etching Mask

AbstractA Si nanocrystal based metal-oxide-semiconductor light-emitting diode (MOSLED) on Si nano-pillar array is preliminarily demonstrated. Rapid self-aggregation of Ni nanodots on Si substrate covered with a thin SiO2 buffered layer is employed as the etching mask for obtaining Si nano-pillar array. Dense Ni nanodots with size and density of 30 nm and 2.8×10 cm-2, respectively, can be formatted after rapid thermal annealing at 850°C for 22 s. The nano-roughened Si surface contributes to both the relaxation of total-internal reflection at device-air interface and the Fowler-Nordheim tunneling enhanced turn-on characteristics, providing the MOSLED a maximum optical power of 0.7 uW obtained at biased current of 375 uA. The optical intensity, turn-on current, power slope and external quantum efficiency of the MOSLED are 140 μW/cm2, 5 uA, 2+-0.8 mW/A and 1×10-3, respectively, which is almost one order of magnitude larger than that of a same device made on smooth Si substrate.

Sign in / Sign up

Export Citation Format

Share Document