The effects of carrier transport phenomena on the spectral and power characteristics of blue superluminescent light emitting diodes

Milani, N. Moslehi; Asgari, Asghar

doi:10.1016/j.physe.2015.01.035

Cited by 13 publications

(3 citation statements)

References 56 publications

(56 reference statements)

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“…Suitable designs of the heterostructures effectively enrich the optical properties of multilayer semiconductors [42]. Semiconductor QDs with various properties are interesting candidates for many optoelectronic applications [43][44][45][46][47][48][49].…”

Section: Introductionmentioning

confidence: 99%

Donor Impurity in CdS/ZnS Spherical Quantum Dots under Applied Electric and Magnetic Fields

2022

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This article presents a theoretical study of the electronic, impurity-related, and nonlinear optical properties of CdS/ZnS quantum dots subjected to electric and magnetic fields. The magnetic field is applied along the z-axis, with the donor impurity always located in the center of the quantum dot. In the case of the electric field, two situations have been considered: applied along the z-axis and applied in the radial direction (central electric field). In both cases, the azimuthal symmetry (around the z-axis) is preserved. In the absence of a magnetic field and considering a central electric field, the system preserves its spherical symmetry both in the presence and in the absence of the donor impurity. The study is carried out in the effective mass approximation and it uses the finite element method to find the eigenfunctions and their corresponding energies, both in the presence and in the absence of the impurity. This work investigates the optical absorption coefficient and the relative change of the refractive index, considering only intraband transitions between l=0 states (states with azimuthal symmetry concerning the z-axis). Calculations are for z-polarized incident radiation. The study shows that the combined effects of a central electric field and a z-directed magnetic field can give rise to a typical core/shell-like quantum confinement with oscillations of the electron ground state. Additionally, it is shown that the presence of the donor impurity suppresses such oscillations and it is responsible for blue shifts in the optical properties and magnifications of the corresponding resonances.

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Section: Introductionmentioning

confidence: 99%

Donor Impurity in CdS/ZnS Spherical Quantum Dots under Applied Electric and Magnetic Fields

2022

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“…QD films exhibit easy color tenability over the entire visible spectrum, broad absorption spectrum and high photoluminescence quantum yield. These attractive properties and advantages make them to be promising for the light emitting applications [5][6][7][8][9]. Solid state white light emitting diodes (WLEDs) as the new generation of light sources can offer the chance to lower thermal resistance and longer lifetime [10,11].…”

Section: Introductionmentioning

confidence: 99%

Fabrication and Characterization of a Light-Emitting Device Based on the CdS/ZnS Spherical Quantum Dots

Hasanirokh

Asgari

Mohammadi

2021

Preprint

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In this work, we focus on the colloidal quantum dot based light-emitting diodes (QD-LEDs) performance. First, we synthesize the spherical QDs with a CdS core that covered with a wider band gap II–VI semiconductor acting as a shell (ZnS). In order to synthesize this nano crystal QDs with structure of CdS/ZnS/CdS/ZnS, we use a reverse micelle process. These four-layer quantum well quantum dots (QWQDs) can generate the white light emission. The positional design of different layers i.e., core/shell QD emitters is a critical factor for white emissive devices. The blue emission generated by CdS core mixes with green/orange components originating from ZnS inner shell and creates an efficiency white light emission. Then, we fabricate a white-QDLED with a device structure of ITO/ ZnO / QD / CBP/ MoO 3 / Al films. A thin film of CdS/ZnS/CdS/ZnS QDs is deposited by electrostatically assembled colloidal QD solutions. The experimental results show that the emission spectra of QDs and current density through the LED are controlled by varying the particle sizes. The peaks of absorbance and Photoluminescence (PL) spectrums get the red shifted as the dot size increases. Furthermore, this QD-LED with a smaller nano particle layer has a higher current density.

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“…On the other hand; light emitters sources made of Ш-N components especially GaN, AlGaN, and AlN, which are used as the nanostructured active regions, have attracted specific attention thanks to their unique material properties as a wide range of emission (ultraviolet to infrared, because their band gaps vary from 0.7 eV for InN, 3.4 eV for GaN, to 6.2 eV for AlN), the higher temperature stability of the threshold current and the luminescence, and high quantum efficiency [49][50][51].…”

Section: Introductionmentioning

confidence: 99%

Power improvement in ridge bent waveguide superluminescent light-emitting diodes based on GaN quantum dots

Rokhi¹,

Asgari²

2021

Phys. Scr.

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In this paper, the performance of ridge-waveguide superluminescent light-emitting diodes (SLED) based on nitride quantum dots has been reported. For this purpose, the three-dimensional Schrodinger equation has been solved numerically by the finite volume method for truncated pyramidal quantum dots as active regions taking into account all spontaneous and piezoelectric effects. To calculate the modal gain in the active region, the traveling-wave rate equations model has been used. We solved the traveling-wave equations coupled with the carrier density rate equation to obtain the output power related to the bias current, numerically. The output power is one of the parameters that describe the performance of a superluminescent light-emitting diode. The output power is studied for the SLEDs with different waveguide structural parameters such as the cavity length and radius of curvature. The temperature-dependent of the SLED output power is also investigated. The maximum output power of the SLED increased up to 0.08 W for the cavity with the length of 1200 mm.

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The effects of carrier transport phenomena on the spectral and power characteristics of blue superluminescent light emitting diodes

Cited by 13 publications

References 56 publications

Donor Impurity in CdS/ZnS Spherical Quantum Dots under Applied Electric and Magnetic Fields

Donor Impurity in CdS/ZnS Spherical Quantum Dots under Applied Electric and Magnetic Fields

Fabrication and Characterization of a Light-Emitting Device Based on the CdS/ZnS Spherical Quantum Dots

Power improvement in ridge bent waveguide superluminescent light-emitting diodes based on GaN quantum dots

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