Semester

Spring

Date of Graduation

2012

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Lane Department of Computer Science and Electrical Engineering

Committee Chair

Lawrence A Hornak

Committee Co-Chair

Jeremy M Dawson

Committee Member

Dimitris Korakakis

Abstract

GaN based optoelectronic devices have had significant impact in solid state lighting. Developing efficient light emitting diodes has been of great research interest in recent years. Electrical modeling of light emitting diodes is now gaining its importance with the development of TCAD tools to have a better understanding of the device structure and to have cost reduction associated with the material and labor.;In this thesis a TCAD model for our device has been developed with the finite element analysis TCAD tool sentaurus from synopsys. The developed model has been validated to the experimental results. The electrical characteristics of the device have been analyzed with the use of band diagrams, current distribution, radiative recombination rate and IV plots.;Different layers of the device have been studied and analyzed and certain design changes to achieve an enhancement in the efficiencies are proposed. The problem of current crowding in LEDs has been widely reported in the literature. In this study passive modeling of the LED structure with PSPICE has been carried out to understand the impact of the conductivities of different layers on the problem of current crowding. With the feedback from the PSPICE model an analytical relation has been determined between the p-GaN layer and n-GaN layer to have uniform current spreading. However, establishing the analytical relation between these layers is experimentally challenging. An alternate design change utilizing transparent conducting AZO contact to p-GaN has been designed and analyzed.

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