InxGa1−xN quantum dots have been fabricated by the selective growth of GaN micropyramid arrays topped with InGaN/GaN quantum wells. The spatially, spectrally, and time-resolved emission properties of these structures were measured using cathodoluminescence hyperspectral imaging and low-temperature microphotoluminescence spectroscopy. The presence of InGaN quantum dots was confirmed directly by ...

Emission dynamics of two InGaN/GaN single quantum well red emitters were investigated through timeresolved photoluminescence (PL) spectroscopy. A clear phase separation, where a higher energy (blue) emission and a lower energy (red) emission appear simultaneously, was observed. The maximum position of blue emission is consistent with the bandgap value of the InGaN quantum well. As the time afte...

We use surface plasmons to increase the light emission efficiency from InGaN/GaN quantum wells by covering these with thin metallic films. Large luminescence enhancements were measured when silver or aluminum layers are deposited 10 nm above an InGaN light emitting layer, whereas no such enhancements are obtained from gold coated samples. The internal quantum efficiencies of quantum wells befor...

InGaN/GaN multiple-quantum-well MQW light-emitting diodes with varied InGaN quantum well thicknesses are fabricated and characterized. The investigation of luminous efficiency versus current density reveals a variety of efficiency droop behaviors. It is found that the efficiency droop can be drastically reduced by increasing the quantum well thickness of the MQW structures. On the other hand, r...

Optically modulated internal strain has been observed in InGaN quantum dots (QDs) deposited on SiN(x) nano masks. The modulated internal strain can induce a number of intriguing effects, including the change of refractive index and the redshift of InGaN A(1)(LO) phonon. The underlying mechanism can be well accounted for in terms of the variation of internal strain through the converse piezoelec...

This paper aims to investigate the light output power (LOP) of InGaN-based light-emitting diodes (LEDs) grown on patterned sapphire substrates (PSSs) with different symmetry. The GaN epitaxial layers grown on the hexagonal lattice arrangement PSS (HLAPSS) have a lower compressive strain than the ones grown on the square lattice arrangement PSS (SLAPSS). The quantum-confined Stark effect (QCSE) ...

The monolithic integration structure of the AlGaN/InGaN/GaN−based high electron mobility transistor (HEMT) and light−emitting diode (LED) is attractive in LED lighting visible light communication (VLC) systems owing to reduction parasitic elements by removing metal interconnections. Due band−offset polarization effect, inserting a certain thickness InGaN layer into traditional AlGaN/GaN single ...

Abstract In this study, the monolithic integration of LEDs with different emission colors (wavelengths 543, 573, and 597 nm) directional radiation profiles was demonstrated. InGaN/GaN nanocolumn arrays ordered in a triangular lattice were prepared side by side, changing diameter n-GaN ( D ). The periodic arrangement nanocolumns led to photonic crystal (PC) effect. band edge wavelength λ B ) InG...

Current injection efficiency and its impact on efficiency-droop in InGaN single quantum well (QW) based light-emitting diodes (LEDs) are investigated. The analysis is based on current continuity relation for drift and diffusion carrier transport across the QW-barrier system. A self-consistent 6-band k p method is used to calculate the band structure for InGaN QW. The analysis indicates that the...

Rational design and synthesis of nanowires with increasingly complex structures can yield enhanced and/or novel electronic and photonic functions. For example, Ge/Si core/shell nanowires have exhibited substantially higher performance as field-effect transistors and low-temperature quantum devices compared with homogeneous materials, and nano-roughened Si nanowires were recently shown to have a...