Materials characterization and transmission analysis in erbium-doped gallium nitride microresonator structures

GaN:Er is an attractive material for room temperature 1.54 pm luminescence enhancement devices for use in telecommunications because it does not experience thermal quenching at room temperature like Si:Er and can be electronically pumped. GaN:Er layers grown by molecular beam epitaxy (MBE) on single crystal substrates have shown excellent room temperature 1.54 [mu]m luminescence, but to integrate GaN:Er into microresonator devices it is necessary to grow a good quality GaN:Er film on an amorphous substrate. This thesis examines the optical properties and morphology of GaN:Er layers grown on Si₃N₄ and SiO₂ substrates, and evaluates two microresonator devices with incorporated GaN:Er layers. GaN:Er layers grown by MBE on SiO₂ and Si₃N₄ substrates were shown to give room temperature luminescence comparable to that of GaN:Er grown on (11 1)Si. GaN:Er layers grown on a buffered oxide etched Si₃N₄ substrate showed the best luminescence. The ability to grow good quality layers on amorphous substrates allows GaN:Er to be used in waveguide devices, the first of which studied was the microring resonator. Microring resonators were made by depositing a blanket GaN:Er layer on patterned Si₃N₄ microring structures. These structures were damaged, and transmission measurements were not possible. When looking at surface roughness measurements it appears that channel waveguide structures are unsuitable for GaN:Er grown on amorphous substrates, and so a ridge waveguide structure is proposed to lower this surface roughness scattering loss. A microcavity with a GaN:Er defect layer and a-Si/a-SiO₂ stacks was fabricated and tested for luminescence enhancement. The refractive index of GaN:Er was determined by reflectance measurements to be 2.1. The layer was not of uniform thickness which led to a broad resonance peak, but a distortion of the spectrum including a lower luminescence at the 1517 nm peak and a higher luminescence at the 1557 nm peak were observed, which suggests enhancement by the microcavity.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Materials Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2001

Author dc:creator

• Gibbons, David M

Advisor dc:contributor.advisor

• Kazumi Wada and Lionel C. Kimerling.

• Materials Science and Engineering.

Statement dc:rights

• MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/114086

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/114086