Study of Carrier Lateral Transport and Internal Quantum Efficiency in InGaN/GaN Light Emitting Diodes with Monte Carlo Method
Date Issued
2010
Date
2010
Author(s)
Lu, I-Lin
Abstract
Efficiency improvement of LED becomes more important when LED starts to play an important role in the applications of lighting and display technology. The efficiency is one of the key factors which impedes the progress of InGaN/GaN LEDs. In this thesis, we study the carrier dynamics in the InGaN/GaN quantum well and try to find what the mechanism limits the device performance. We have developed a Monte Carlo simulation program to study the lateral transport of free carriers in the InGaN/GaN quantum well. First, the radiative recombination rate and radiative lifetime of electrons are calculated by a self-consistent Poisson, Schrodinger and drift-diffusion solver. When carriers are injected into the quantum well, we calculated the lateral electron mobility and estimated the maximum internal quantum efficiency by the Monte Carlo method. The effects of alloying scattering, charged dislocation scattering, interface roughness scattering, and electron-electron scattering have been included in our model. The study of indium composition, interface roughness, carrier density, temperature, and dislocations are included in this thesis. The results show that the non-radiative recombination caused by defect trapping plays a dominating role for higher indium composition. This limits the internal quantum efficiency. Our results suggest that reducing QCSE and dislocation density are still the key factors to improve the internal quantum efficiency.
Subjects
InGaN
GaN
quantum well
Monte Carlo method
radiative lifetime
scattering
dislocation
lateral mobility
diffusion length
efficiency
LED
Type
thesis
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