| Titre : | Simulation of the effect of quantum wells on light-emitting diodes |
| Auteurs : | Baara, Auteur ; Toufik Tibermacine, Directeur de thèse |
| Type de document : | Monographie imprimée |
| Editeur : | Biskra [Algérie] : Faculté des Sciences Exactes et des Sciences de la Nature et de la Vie, Université Mohamed Khider, 2023 |
| Format : | 1vol(54) |
| Mots-clés: | Light emitting diodes, InGaN/GaN, Quantum wells, Simulation, SILVACO-ATLAS. |
| Résumé : |
Using the SILVACO software, we have simulated the effect of quantum wells on the electrical and optical characteristics of MQWs light emitting diodes. The quantum wells InGaN are inserted at the junction between n-GaN and p-GaN. In an ideal case, electrons of type n diffuse towards the conduction band of the quantum wells. Similarly, holes coming from the p-type diffuse towards the valence band of the quantum wells. The carriers then locate themselves in the wells. As carrier densities n and p are large in the wells. Radiation recombination becomes faster than non-radiative recombination, so the efficiency of the device is increased. In addition, the oscillation force is large in a quantum well, which also leads to an increase in the efficiency of the LED in comparison to that of a homo-junction or hetero-junction. Nevertheless, due to the increasing series resistance, a larger number of wells would bring a higher turn-on voltage. In addition, the interface of MQWs would become rougher with increase of wells number, and deteriorate the emission efficiency. Therefore, it is proposed that the interface of MQWs should be taken into account when exploring the optimal QWs number to obtain high performance InGaN/GaN LEDs.
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| Sommaire : |
DedicationI
Thanks and appreciationII AbstractIII Table of contentsIV List of figuresVII List of tablesIX General introduction1 Chapter I: Basic Concepts on Semiconductors I.1.Introduction2 I.2.Semiconductors2 I.3.Types of semiconductors3 I.3.1.Intrinsic semiconductors3 I.3.2.Extrinsic semiconductors4 I.3.2.1.Semiconductor type N4 I.3.2.1.Semiconductor type P5 I.4.Charge carrier concentration6 I.5.Direct and indirect semiconductors7 I.5.1.Direct gap semiconductor8 I.5.2.Indirect gap semiconductor8 I.6.Generation–Recombination9 I.6.1.Generation9 I.6.2.Recombination9 I.6.2.1.Radiative recombination10 I.6.2.2.Auger recombination10 I.6.2.3.Shockley Read Hall recombination11 I.6.2.4.Surface recombination12 I.7.Gallium nitride GaN layer13 I.8.Indium gallium nitride InGaN layer13 I.9.Aluminum gallium nitride AlGaN layer14 I.10.InGaN/GaN quantum wells14 Chapter II: Light Emitting Diodes II.1.Introduction15 V II.2.Definition15 II.3.PN junction16 II.3.1.Forward bias of the junction17 II.3.2.Reverse bias of the junction18 II.4.Principle of LED operation19 II.5.Classification of light emitting diodes20 II.5.1.Structure classification20 II.5.1.1.Homojunction light emitting diodes20 II.5.1.2.Heterojunction light emitting diodes21 II.5.1.3.Quantum well LEDs22 II.5.2.Power classification23 II.5.2.1.Low power LED23 II.5.2.2.High-Power LED24 II.5.3.Emission spectra classification25 II.5.3.1.Monochromatic light emitting diodes25 II.5.3.2.White light emitting diodes26 II.5.3.3.Infrared light emitting diodes26 II.6.Properties of light emitting diodes26 II.6.1.Optical properties26 II.6.1.1.Quantum efficiencies26 II.6.1.2.Emission spectra27 II.6.1.3.Optical power27 II.6.1.4.Luminous efficiency of light emitting diodes28 II.6.2.Electrical properties29 II.7.Applications of LEDs30 II.8.Advantages and disadvantages of light emitting diodes30 II.8.1.Advantages30 II.8.2.Disadvantages31 Chapter III: SILVACO-ATLAS and simulation results III.1.Introduction32 III.2.Presentation of the SILVACO program package32 III.2.1.ATLAS33 III.2.1.1.Deckbuild34 VI III.2.1.2.Tonyplot35 III.2.2.Basic semiconductor equations in ATLAS-SILVACO35 III.2.3.Syntax of a program in ATLAS36 III.2.3.1.Mesh36 III.2.3.2.Region37 III.2.3.3.Electrode38 III.2.3.4.Doping39 III.2.4.Specification of material parameters and physical models40 III.2.4.1.Materials40 III.2.4.2.Models40 III.2.5.Selection of the numerical method41 III.2.6.Solution Specification41 III.2.6.1.Log41 III.2.6.2.Solve41 III.2.6.3.Save42 III.2.7.Analyse of results42 III.2.7.1.EXTRACT42 III.2.7.2.TONYPLOT42 III.3.Simulation results43 III.3.1.Representation of the simulated structure43 III.3.2.Simulation parameters of the LED45 III.3.3.Current-Voltage characteristic46 III.3.4.Spectral power47 III.3.5.Luminous Power48 III.3.6.Spectral power of 2QWs at different voltages49 III.3.7.Internal quantum efficiency50 III.3.8. Comparison of ordinary and multiple quantum well light-emitting diodes52 General conclusion54 References |
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| Cote | Support | Localisation | Statut |
|---|---|---|---|
| MPHY/617 | Mémoire master | bibliothèque sciences exactes | Consultable |
