&[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.

Reduction of Thermal Resistance and Optical Power Loss Using Thin-Film Light-Emitting Diode (LED) Structure

2015 ◽  
Vol 62 (11) ◽  
pp. 6925-6933 ◽  
Author(s):  
Huan Ting Chen ◽  
Yuk Fai Cheung ◽  
Hoi Wai Choi ◽  
Siew Chong Tan ◽  
S. Y. Hui
Keyword(s):  
Thin Film ◽  
Thermal Resistance ◽  
Power Loss ◽  
Light Emitting Diode ◽  
Optical Power ◽  
Light Emitting

(Invited) High Brightness, Large Scale GaN Based Light-Emitting Diode Grown on 8-Inch Si Substrate

2014 ◽  
Vol 61 (4) ◽  
pp. 71-78
Author(s):  
S.-J. Lee ◽  
H.-J. Park ◽  
J.-B. Park ◽  
D.-W. Jeon ◽  
J. H. Baek ◽  
...  
Keyword(s):  
Large Scale ◽  
Light Emitting Diode ◽  
Si Substrate ◽  
High Brightness ◽  
Light Emitting

N-face GaN substrate roughening for improved performance GaN-on-GaN LED

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ezzah Azimah Alias ◽  
Muhammad Esmed Alif Samsudin ◽  
Steven DenBaars ◽  
James Speck ◽  
Shuji Nakamura ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Light Emitting Diode ◽  
Optical Power ◽  
Ammonium Hydroxide ◽  
Content Type ◽  
Light Emitting ◽  
Gan Led ◽  
Improved Performance ◽  
Substrate Roughening

Purpose This study aims to focus on roughening N-face (backside) GaN substrate prior to GaN-on-GaN light-emitting diode (LED) growth as an attempt to improve the LED performance. Design/methodology/approach The N-face of GaN substrate was roughened by three different etchants; ammonium hydroxide (NH4OH), a mixture of NH4OH and H2O2 (NH4OH: H2O2) and potassium hydroxide (KOH). Hexagonal pyramids were successfully formed on the surface when the substrate was subjected to the etching in all cases. Findings Under 30 min of etching, the highest density of pyramids was obtained by NH4OH: H2O2 etching, which was 5 × 109 cm–2. The density by KOH and NH4OH etchings was 3.6 × 109 and 5 × 108 cm–2, respectively. At standard operation of current density at 20 A/cm2, the optical power and external quantum efficiency of the LED on the roughened GaN substrate by NH4OH: H2O2 were 12.3 mW and 22%, respectively, which are higher than its counterparts. Originality/value This study demonstrated NH4OH: H2O2 is a new etchant for roughening the N-face GaN substrate. The results showed that such etchant increased the density of the pyramids on the N-face GaN substrate, which subsequently resulted in higher optical power and external quantum efficiency to the LED as compared to KOH and NH4OH.

scholarly journals Silicon Quantum Dot Light Emitting Diode at 620 nm

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 318 ◽  
Author(s):  
Hiroyuki Yamada ◽  
Naoto Shirahata
Keyword(s):  
Quantum Dot ◽  
High Performance ◽  
Light Emitting Diode ◽  
Optically Active ◽  
Driving Voltage ◽  
Device Structure ◽  
Light Emitting ◽  
Naked Eye ◽  
Turn On ◽  
Silicon Quantum Dot

Here we report a quantum dot light emitting diode (QLED), in which a layer of colloidal silicon quantum dots (SiQDs) works as the optically active component, exhibiting a strong electroluminescence (EL) spectrum peaking at 620 nm. We could not see any fluctuation of the EL spectral peak, even in air, when the operation voltage varied in the range from 4 to 5 V because of the possible advantage of the inverted device structure. The pale-orange EL spectrum was as narrow as 95 nm. Interestingly, the EL spectrum was narrower than the corresponding photoluminescence (PL) spectrum. The EL emission was strong enough to be seen by the naked eye. The currently obtained brightness (∼4200 cd/m2), the 0.033% external quantum efficiency (EQE), and a turn-on voltage as low as 2.8 V show a sufficiently high performance when compared to other orange-light-emitting Si-QLEDs in the literature. We also observed a parasitic emission from the neighboring compositional layer (i.e., the zinc oxide layer), and its intensity increased with the driving voltage of the device.

A Yellow InGaP Light Emitting Diode Epitaxially Grown on Si Substrate

2015 ◽  
Author(s):  
Cong Wang ◽  
Bing Wang ◽  
Kenneth Eng Kian Lee ◽  
Soon Fatt Yoon ◽  
Jurgen Michel
Keyword(s):  
Light Emitting Diode ◽  
Si Substrate ◽  
Light Emitting

Time-Resolved Transport of Electrons and Holes in Conjugated Polymers

1999 ◽  
Vol 561 ◽  
Author(s):  
D. Pinner ◽  
R. H. Friend ◽  
N. Tessler
Keyword(s):  
Conjugated Polymers ◽  
Temporal Evolution ◽  
Exponential Tail ◽  
Time Resolved ◽  
Light Emitting ◽  
Turn On ◽  
Initial Rise ◽  
Order Of Magnitude ◽  
Slow Rise ◽  
Polymer Light Emitting Diodes

ABSTRACTDetailed experimental and theoretical analysis of the pulsed excitation of polymer light emitting diodes is presented. We find a set of universal transient features for different device configurations which can be reproduced using our phenomenological numerical model. We find that the temporal evolution of the electroluminescence can be characterised by five main features: i) a delay followed by; ii) fast initial rise at turn-on followed by; iii) a slow rise (slower by at least one order of magnitude); iv) fast modulation (<15ns, unresolved) at turn-off followed by v) a long-lived exponential tail. We suggest a method for extracting mobility values which is found to be compatible with CW drive schemes. Mobilities for holes and electrons are extracted for a poly(p-phenylenevinylene) co-polymer and poly(di-octyl fluorene).

UVA light-emitting diode grown on Si substrate with enhanced electron and hole injections

2017 ◽  
Vol 42 (21) ◽  
pp. 4533 ◽  
Author(s):  
Zi-Hui Zhang ◽  
Chunshuang Chu ◽  
Ching Hsueh Chiu ◽  
Tien Chang Lu ◽  
Luping Li ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Si Substrate ◽  
Light Emitting ◽  
Uva Light

Enhanced Optical Power of InGaN/GaN Light-Emitting Diode by AlGaN Interlayer and Electron Blocking Layer

2012 ◽  
Vol 24 (22) ◽  
pp. 1991-1994 ◽  
Author(s):  
Sang-Jun Lee ◽  
Chu-Young Cho ◽  
Sang-Hyun Hong ◽  
Sang-Heon Han ◽  
Sukho Yoon ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Optical Power ◽  
Blocking Layer ◽  
Electron Blocking Layer ◽  
Light Emitting
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