Date

2018

Document Type

Thesis

Degree

Master of Science

Department

Electrical Engineering

First Adviser

Nelson Tansu

Abstract

AbstractVarious strain-compensated InGaN-AlGaInN quantum well (QW) structures are investigated by self-consistent 6-band k∙p method, which considers valence band mixing, the strain effect, spontaneous and piezoelectric polarizations and the carrier screening effect, for their spontaneous emission and gain properties. The InGaN QW with In-content of 28% is sandwiched by AlGaInN barriers, which are Al0.2Ga0.8N, Al0.56Ga0.32In0.12N, Al0.72Ga0.13In0.15N, Al0.78Ga0.1In0.12N, and Al0.82Ga0.1In0.08N, with corresponding band gaps of 3.821eV, 4.156eV, 4.465eV, 4.765eV, and 5.065eV, respectively. Both the spontaneous emission spectra and optical gain properties of strain-compensated InGaN–AlGaInN QWs reveal enhancement in comparison to those of conventional InGaN–GN QWs. The enhancement factors of spontaneous emission spectra and peak gain properties for different barrier structures are found to follow a parabolic trend. This indicates differing amounts of improvement of the radiative efficiency for light emitting diodes. This study shows that there is an optimized composition for an AlGaInN barrier layer surrounding an In0.28Ga0.72N quantum well between the bandgaps of 4.156eV and 4.465eV that will obtain the highest spontaneous emission rate and gain properties.

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