Date of Award

12-2013

Degree Name

MS in Electrical Engineering

Department

Electrical Engineering

Advisor

Xiaomin Jin

Abstract

Improving energy efficient lighting is a necessary step in reducing energy consumption.Lighting currently consumes 17% of all U.S. residential and commercial electricity, but a report from the U.S. Office of Energy Efficiency and Renewable Energy projects that switching to LED lighting over the next 20 years will save 46% of electricity used in lighting.GaN LEDs are used for their efficient conversion of electricity to light, but improving GaN efficiency requires optically engineering the chip to extract more light.Total internal reflection limits GaN LED performance since light must approach the chip surface within 23.6° of normal to escape into air.This thesis systematically studies the effect of index of refraction, material thickness, and nano-grating period on light extraction efficiency.An ITO layer is added to the LED surface to increase the critical angle of light, and standing wave analysis is used to optimize material thicknesses.When these results are combined with the best grating period, light output improves by 254% over the unmodified LED.

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