Ultrasmall blue InGaN micro-light-emitting diodes (µLEDs) with areas from 10−4 to 0.01 mm2 were fabricated study their optical and electrical properties. The peak external quantum efficiencies (EQEs) of the smallest largest µLEDs 40.2 48.6%, respectively. difference in EQE was nonradiative recombination originating etching damage. This decrease is less severe than that red AlInGaP LEDs. efficiency droop at 900 A/cm2 µLED 45.7%, compared 56.0% for largest, lower because improved current...

We demonstrate very high luminous efficacy green light-emitting diodes employing Al0.30Ga0.70N cap layer grown on patterned sapphire substrates by metal organic chemical vapor deposition. The peak external quantum efficiency and efficacies were 44.3% 239 lm/w, respectively. At 20 mA (20 A/cm2) the light output power was 14.3 mW, forward voltage 3.5 V, emission wavelength 526.6 nm, 30.2%. These results are among highest reported values for InGaN based diodes.

Micro-light-emitting diodes (µLEDs) with tunnel junction (TJ) contacts were grown entirely by metalorganic chemical vapor deposition. A LED structure was grown, treated UV ozone and hydrofluoric acid, reloaded into the reactor for TJ regrowth. The silicon doping level of n++-GaN varied to examine its effect on voltage. µLEDs from 2.5 × 10−5 0.01 mm2 in area processed, voltage penalty smallest µLED at 20 A/cm2 0.60 V relative that a standard indium tin oxide. peak external quantum efficiency 34%.

We demonstrate efficient semipolar (11-22) 550 nm yellow/green InGaN light-emitting diodes (LEDs) with In0.03Ga0.97N barriers on low defect density GaN/patterned sapphire templates. The were clearly identified, and no clusters observed by atom probe tomography measurements. LEDs (0.1 mm2 size) show an output power of 2.4 mW at 100 mA a peak external quantum efficiency 1.3% drop. In addition, the exhibit small blue-shift only 11 as injection current increases from 5 to mA. These results...

Plasma-enhanced atomic layer deposition was used to grow molybdenum disulfide films using (tBuN)2(NMe2)2Mo and a remote H2S-Ar plasma as coreactants on three different substrates: thermal oxide silicon, c-plane sapphire, epitaxial GaN sapphire. Depositions were carried out at 250 °C. The substrates’ effect the growth of MoS2 investigated through resonance Raman spectroscopy, x-ray photoelectron force microscopy. In addition, transmission electron microscopy performed deposited...

In this study, water removal techniques were experimentally developed as a diagnostic tool for the investigation of polymer electrolyte membrane (PEM) fuel cell performance in order to achieve consistent, reliable and repeatable performance. The three methods include orientation, shaking hydraulic permeation, instantaneous improvement had been observed when these employed. All experiments carried out with single PEMFC active surface area 50 cm2. Pure hydrogen was used air oxidant. It found...

The performance of LEDs with Ga‐doped ZnO (Ga:ZnO) and Sn‐doped In 2 O 3 (ITO) current‐spreading layers (CSLs) has been evaluated at high injection current densities. electron beam‐hydrothermally deposited Ga:ZnO transparent CSLs showed improved compared to beam ITO all External quantum efficiency wall plug were both higher for blue emitting ZnO. Luminous efficacy increased greatly the ZnO‐based CSL a peak value 113 lm/W 82 ITO‐based CSL, 37% improvement.

Semipolar InGaN 432 nm light-emitting diodes were demonstrated on semipolar GaN templates grown patterned sapphire. Packaged devices exhibited a light output power of 4.7 mW at 100 A/cm2 and peak external quantum efficiency 1.3%. Atom probe tomography characterization indicated detectable bending in wells as result significant roughening from regrowth the templates, while no indium clustering effect was observed. Light extraction simulations also performed to estimate improvement using...

Efficient InGaN-based 444 nm blue light-emitting diodes (LEDs) were fabricated on low-defect-density semipolar GaN templates grown patterned r-sapphire. At 20 A/cm2, the packaged LEDs exhibited a light output power of 2.9 mW (17.8 at 100 A/cm2) and record peak external quantum efficiency 6.4% showing negligible droop shift with drive currents up to A/cm2. In addition, we demonstrated extraction simulations for template, which showed that structured pattern is not only beneficial limiting...

A novel approach for producing and tuning the emission of a colloidal dispersion amorphous porous silicon nanoparticles <italic>via</italic> controlled oxidation disorder increase.

Improved turn-on voltages and reduced series resistances were realized by depositing highly Si-doped n-type GaN using molecular beam epitaxy on polarization-enhanced p-type InGaN contact layers grown metal–organic chemical vapor deposition. We compared the effects of different Si doping concentrations addition forward p–n diodes light-emitting diodes, found that increasing from 1.9 × 1020 to 4.6 cm−3 including a doped at junction both contributed reductions in depletion width, resistance 4.2...

We report continuous-wave (CW) blue semipolar (202¯1) III-nitride laser diodes (LDs) that incorporate limited area epitaxy (LAE) n-AlGaN bottom cladding with thin p-GaN and ZnO top layers. LAE mitigates LD design limitations arise from stress relaxation, while layers reduce epitaxial growth time temperature. Numerical modeling indicates reduces the internal loss increases differential efficiency of TCO clad LDs. Room temperature CW lasing was achieved at 445 nm for a ridge waveguide...

This work proposes that roughening on the backside of a GaN substrate prior to InGaN-based LED growth not only simplifies fabrication steps for but also cleans other side was served as surface LED. As compared post-roughening, forward voltage has reduced at 3.48 V through pre-roughening. Further, peak external quantum efficiency pre-roughened is 21.6% <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mn>12</mml:mn> <mml:mspace width="thickmathspace" /> <mml:mrow...

Acmite ( NaFeSi 2 O 6 ) films were formed on steel coupons via solvothermal reaction of silica, sodium hydroxide, and 1, 4‐butanediol in an autoclave under autogenous pressure. Systematic variation processing variables led to homogenous coatings comprised pinacoidal acmite grains with average grain size ~33 μm. The produced the from reactant conditions 0.635 m SiO , 2.546 NaOH 3.087 1,4‐butanediol for 72 h at 240°C.

Group III impurity doped ZnO thin films were deposited on MgAl 2 O 3 substrates using a simple low temperature two‐step deposition method involving atomic layer and hydrothermal epitaxy. Films with varying concentrations of either Al, Ga, or In evaluated for their optoelectronic properties. Inductively coupled plasma emission spectroscopy was used to determine the concentration dopants within films. While Al Ga‐doped showed linear incorporation rates addition precursors salts in growth...

Starting from crystalline silicon we synthesised bright suspensions of amorphous porous nanoparticles through unconventional stain etching. Upon excitation with UV light, this novel nanostructured material gives rise to an intense red photoluminescence (PL) which resembles that some nanostructures. We studied the properties prepared using a number cutting-edge characterization techniques such as TEM, SEM and EDX. The complete crystalline-to-amorphous phase transition, confirmed by...

Raman spectroscopy can provide a detailed analysis of mechanical stress in crystalline materials through the measurement shifts vibrational frequency. However, ambient temperature drift during measurements lead to inaccurate values. Herein, 2D mapping gallium nitride (GaN) and aluminum indium phosphide (AlInGaP) epitaxial films within packaged light‐emitting diode (LED) devices reveals micrometer‐scale localized distributions. A temperature‐corrected method is developed evaluate InGaN LED...

This work proposes that roughening on the backside of a GaN substrate prior to InGaN-based LED growth not only simplifies fabrication steps for but also cleans other side was served as surface LED. As compared post-roughening, forward voltage has reduced at 3.48 V through pre-roughening. Further, peak external quantum efficiency pre-roughened is 21.6% 12mA/cm2, while post-roughened 20.6% at14mA/cm2.

Although silicon (Si) currently dominates the semiconductor industry, its small 1.1 eV band gap limits maximum operating temperature, which restricts use in high-temperature, high-power devices. Gallium nitride (GaN) is an attractive with wide bandgap (3.4 eV), high electron mobility (1700 cm 2 /Vs), saturation velocity (3 x 10 7 cm/s), large critical breakdown field (2 MV/cm), and thermal stability. The capabilities of GaN allow for a reduction device size, can conserve physical space if...