Numerical Simulation of Optoelectronic Properties of Nonpolar and Semipolar InGaN/GaN Quantum Well Light Emitting Diodes
Date Issued
2009
Date
2009
Author(s)
Huang, Hung-Hsun
Abstract
This thesis discusses the optical characteristics of a nonpolar and semipolar InGaN/GaN quantum well with different indium compositions, quantum well widths, and injection carrier densities. Also, we have studied the properties of valence band structure of the semipolar InGaN alloy films with arbitrary crystal growth orientations to discuss the key issue of designing a polarized light source. The self-consistent Poisson and 6×6 k·p Schrödinger solver has been applied to study the band structures in nonpolar a-plane and semipolar InGaN-based quantum well light emitting diodes (LEDs). For nonpolar a-plane quantum well structure, we find that the larger indium composition and smaller well width make the energy separation of |Y''>-like state to |X''>-like state larger, and as a result enhance the polarization ratio of light. However, the polarization ratio decreases as the carrier injection increases, which might be a drawback for high power applications. The optical polarization properties of semipolar (10-1-3), (11-22),and θ=75 degree InGaN/GaN quantum well were also investigated. Basically, we have studied the optimization condition for designing the nonpolar a-plane and semipolar InGaN quantum well LED for applications, such as liquid crystal display backlight modules and lasers, which would be useful information for device designs.
Subjects
nonpolar
a-plane
semipolar
InGaN
GaN
quantum well
Poisson equation
Schrodinger equation
k.p method
polarization ratio
spontaneous emission
LED
Type
thesis
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