Light efficiency enhanced quantum dot color conversion layer based on a distributed Bragg reflector

Quantum-dot (QD) photonic-crystal (PC) surface-emitting laser (SEL) devices with bottom distributed Bragg reflector (DBR) were fabricated based on vertical-cavity SEL structure with top DBR completely removed. Two-dimensional (2D) PCs were deeply etched through QD multilayers to yield strong diffraction coupling. Room-temperature optically pumped lasing emissions at 1194 nm and 1296 nm were demonstrated for two lattice periods of 360 nm and 395 nm, respectively. Two lasing wavelengths separated over 100 nm; however, there were less than two times difference in threshold power densities while slope efficiencies were comparable. The unique spectral gain characteristics of QDs were considered in interpretation of gain-cavity detuning. Moreover, simulation revealed the sub-cavity should be designed so that its resonant wavelength is in phase with lasing wavelength.

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Modeling and Simulation of a Resonant-Cavity-Enhanced InGaAs/GaAs Quantum Dot Photodetector

Advances in Condensed Matter Physics ◽

10.1155/2015/847510 ◽

2015 ◽

Vol 2015 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

W. W. Wang ◽

F. M. Guo ◽

Y. Q. Li

Keyword(s):

Quantum Dot ◽

Dark Current ◽

Reverse Bias ◽

Detection Efficiency ◽

Resonant Cavity ◽

Bragg Reflector ◽

Distributed Bragg Reflector ◽

Device Structure ◽

High Quantum Efficiency ◽

Gaas Quantum Dot

We simulated and analyzed a resonant-cavity-enhancedd InGaAs/GaAs quantum dot n-i-n photodiode using Crosslight Apsys package. The resonant cavity has a distributed Bragg reflector (DBR) at one side. Comparing with the conventional photodetectors, the resonant-cavity-enhanced photodiode (RCE-PD) showed higher detection efficiency, faster response speed, and better wavelength selectivity and spatial orientation selectivity. Our simulation results also showed that when an AlAs layer is inserted into the device structure as a blocking layer, ultralow dark current can be achieved, with dark current densities 0.0034 A/cm at 0 V and 0.026 A/cm at a reverse bias of 2 V. We discussed the mechanism producing the photocurrent at various reverse bias. A high quantum efficiency of 87.9% was achieved at resonant wavelength of 1030 nm with a FWHM of about 3 nm. We also simulated InAs QD RCE-PD to compare with InGaAs QD. At last, the photocapacitance characteristic of the model has been discussed under different frequencies.

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OPTIMAL DESIGN OF SINGLE-PHOTON SOURCE EMISSION FROM A QUANTUM-DOT IN MICRO-PILLAR MICROCAVITY

International Journal of Quantum Information ◽

10.1142/s0219749905001419 ◽

2005 ◽

Vol 03 (supp01) ◽

pp. 229-238 ◽

Cited By ~ 2

Author(s):

Y.-L. D. HO ◽

T. CAO ◽

P. S. IVANOV ◽

M. J. CRYAN ◽

I. J. CRADDOCK ◽

...

Keyword(s):

Quantum Dot ◽

Spontaneous Emission ◽

Single Photon ◽

Collection Efficiency ◽

Large Fraction ◽

Broad Band ◽

Fdtd Method ◽

Bragg Reflector ◽

Dipole Source ◽

Distributed Bragg Reflector

We have modelled wavelength scale micro-pillar microcavities of group III-V semiconductor materials using the 3-D finite difference time domain (FDTD) method. A broad band dipole source within the microcavity probes the microcavity mode structure and spectrum. We then investigated the modifications to spontaneous emission of photons form narrowband emitters (e.g. quantum dots) at the centre of the resonance. We find strongly enhanced emission due to small modal volumes and high quality factor (Q-factor). A large fraction of the quantum-dot spontaneous emission is coupled into the fundamental cavity mode. Increasing the number of mirror pairs in the bottom distributed Bragg reflector (DBR) obviously reduces the bottom light leakage, leading to light collection efficiency up to 90%. Moreover, we are now looking at more sophisticated structures with both lateral and perpendicular confinements based on annular and photonic crystal defect cavities in order to suppress the remaining sidewall scattering.

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Improved Color Purity of Monolithic Full Color Micro-LEDs Using Distributed Bragg Reflector and Blue Light Absorption Material

Coatings ◽

10.3390/coatings10050436 ◽

2020 ◽

Vol 10 (5) ◽

pp. 436 ◽

Cited By ~ 1

Author(s):

Shao-Yu Chu ◽

Hung-Yu Wang ◽

Ching-Ting Lee ◽

Hsin-Ying Lee ◽

Kai-Ling Laing ◽

...

Keyword(s):

Blue Light ◽

Light Absorption ◽

Bragg Reflector ◽

Color Purity ◽

Distributed Bragg Reflector ◽

Light Emitting ◽

Full Color ◽

Conversion Materials ◽

Bottom Side ◽

Color Conversion

In this study, CdSe/ZnS core-shell quantum dots (QDs) with various dimensions were used as the color conversion materials. QDs with dimensions of 3 nm and 5 nm were excited by gallium nitride (GaN)-based blue micro-light-emitting diodes (micro-LEDs) with a size of 30 μm × 30 μm to respectively form the green and red lights. The hybrid Bragg reflector (HBR) with high reflectivity at the regions of the blue, green, and red lights was fabricated on the bottom side of the micro-LEDs to reflect the downward light. This could enhance the intensity of the green and red lights for the green and red QDs/micro-LEDs to 11% and 10%. The distributed Bragg reflector (DBR) was fabricated on the QDs color conversion layers to reflect the non-absorbed blue light that was not absorbed by the QDs, which could increase the probability of the QDs excited by the reflected blue light. The blue light absorption material was deposited on the DBR to absorb the blue light that escaped from the DBR, which could enhance the color purity of the resulting green and red QDs/micro-LEDs to 90.9% and 90.3%, respectively.

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