Proton-Implanted Optical Waveguides and Integrated Optical Detectors in Gallium Arsenide

Citation

Stoll, Harold McDowell (1974) Proton-Implanted Optical Waveguides and Integrated Optical Detectors in Gallium Arsenide. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/m0zg-j870. https://resolver.caltech.edu/CaltechTHESIS:07082021-224732104

Abstract

Defect-associated energy levels which appear within the forbidden energy gap of proton-irradiated gallium arsenide give rise both to free carrier compensation and to additional near band-edge optical attenuation. These damage-induced changes in the electrical and optical properties of gallium arsenide have been exploited in the fabrication of passive optical waveguides and waveguide-compatible detectors suitable for use in integrated optical circuits. In order to understand the physical processes which underlie the operation of these structures and devices and, thereby, to suggest ways in which the irradiation and post-irradiation fabrication parameters may be optimized, a model has been constructed which explains the experimentally observed electrical and optical properties of proton-irradiated gallium arsenide. Using this model and data obtained by other investigators, a self consistent analysis of the optical confinement and attenuation properties of waveguides formed by irradiating n-type gallium arsenide with 300 keV protons has been made: Optical confinement is found to result from the so-called plasma depression effect; optical attenuation is found to be due to a combination of dissipative scattering and absorption by thermal spikes and dipole-assisted transitions between defect levels and the band continua. The model is also used to make a preliminary analysis of an integrated optical detector fabricated using the same proton-irradiation technique.

Thesis Files