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Growth, processing and chracterization of gallium nitride based coaxial LEDs grown by MOVPE


Please use this identifier to cite or link to this item: http://hdl.handle.net/1928/21070

Growth, processing and chracterization of gallium nitride based coaxial LEDs grown by MOVPE

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dc.contributor.author Rishinaramangalam, Ashwin
dc.date.accessioned 2012-08-28T17:31:52Z
dc.date.available 2012-08-28T17:31:52Z
dc.date.issued 2012-08-28
dc.date.submitted July 2012
dc.identifier.uri http://hdl.handle.net/1928/21070
dc.description.abstract Gallium nitride (GaN) based coaxial (core-shell type) light emitting diodes (LEDs) offer a wide range of advantages. The active region of these LEDs is located on non-polar, {1-100} m-plane GaN sidewalls, which helps eliminate the quantum confined Stark effect (QCSE) and improve the radiative recombination efficiency of LEDs. The recent evolution of a catalyst free, scalable, repeatable and industrially viable device quality GaN nanowire and nanowall metal organic vapor phase epitaxy (MOVPE) growth process has enhanced the possibility of these LEDs going into production from laboratory. Previous work has shown that these nanowires exhibited an intense photoluminescence (PL), in spite of their large surface-area to volume ratio, and lasing was observed when these nanowires were optically pumped at high intensity. In this dissertation, it is shown that as long as the GaN three dimensional (3D) structures have their critical dimension below a micron, the threading defect (TD) density along the c- direction approaches zero. A TD that enters into this structure bends towards the surface vii ({1-100} m-plane side wall) in its vicinity, thereby reducing its dislocation line energy. The possibility of growing zero defect GaN templates is extremely important in the breakdown voltage improvement, the reverse bias leakage current reduction and efficiency droop reduction. This growth method has also been extended to device quality micron sized features, thereby presenting us with opportunity to study and explore LEDs of different sizes and shapes. In addition to the microstructure growth, two different repeatable approaches have been identified and demonstrated for the microelectronic processing of these micron-sized LEDs. Despite being far from perfect, the characterization results obtained from these LEDs have been encouraging. The technological challenges associated with the fabrication of the coaxial LEDs are also discussed in this dissertation. en_US
dc.description.sponsorship Smart Lighting Engineering Research Center funded by the National Science Foundation. en_US
dc.language.iso en_US en_US
dc.subject Gallium Nitride en_US
dc.subject LEDs en_US
dc.subject MOVPE en_US
dc.subject coaxial en_US
dc.subject MOCVD en_US
dc.subject crystal growth en_US
dc.subject.lcsh Light emitting diodes.
dc.subject.lcsh Gallium nitride.
dc.subject.lcsh Metal organic chemical vapor deposition.
dc.subject.lcsh Nanowires.
dc.title Growth, processing and chracterization of gallium nitride based coaxial LEDs grown by MOVPE en_US
dc.type Dissertation en_US
dc.description.degree Electrical Engineering en_US
dc.description.level Doctoral en_US
dc.description.department University of New Mexico. Dept. of Electrical and Computer Engineering en_US
dc.description.advisor Hersee, Stephen
dc.description.advisor Balakrishnan, Ganesh
dc.description.committee-member Balakrishnan, Ganesh
dc.description.committee-member Krishna, Sanjay
dc.description.committee-member Han, Sang
dc.description.committee-member Rotter, Thomas

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