In0.22Ga0.78N/In0.06Ga0.94N multiple quantum well (MQW) microdisks with a size of 5.6 μm in diameter have been fabricated by photolithography and ion beam etching. Time-resolved photoluminescence (PL) has been employed to study optical transitions in MQW structure and microdisks. The dominant emissions from both MQW structures and microdisks were from localized exciton transitions. It was found in the microdisks that the low energy shoulder of the PL spectrum was quenched, and that the spontaneous emission line width was narrower while its intensity was enhanced with respect to that of the MQWs, which may be related to microcavity effects in the microdisks. A blue shift of the PL peak from the MQW microdisks compared with that in the MQW structures was also observed, and can be understood in terms of a reduced piezoelectric field due to strain relief in the microdisks. Microdisks with grating patterned micro-couplers around the disk edges were also fabricated by e-beam lithography to enhance light extraction from the microdisks. Near-field scanning optical microscopy (NSOM) was employed to map the near-field fluorescence images of the microdisks, which showed a strong emission preference in certain directions. The potential applications of III-nitride microdisks for optical interconnects and integration are also discussed.
|Number of pages
|Proceedings of SPIE - The International Society for Optical Engineering
|Published - 1999
|Proceedings of the 1999 Photonics Technology into the 21st Century: Semiconductors, Microstructures, and Nanostructures - Singapore, Singapore
Duration: Dec 1 1999 → Dec 3 1999