GaN-based microcavities : fabrication, characterisation and development

• Main Author: Bejtka, Katarzyna
• Published: University of Strathclyde 2008
• Subjects: 621.38152
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501651

This thesis describes the fabrication and characterisation of double dielectric mirror GaN-based microcavities (MCs) along with investigation of the properties of various materials required for them, including GaN on AlInN, AlGaN, AlInGaN, and the use of FS-GaN substrate. Several processing routes for MC fabrication are detailed, with characterisation measurements after each step and for completed structures. Strong coupling between an exciton and a photon was observed for some approaches. The structures were grown by MOVPE and MBE on FS-GaN, sapphire and silicon substrates. Microcavities were fabricated using various techniques for substrate removal in order to access the back-side of active region for deposition of the bottom mirror. The finalised structures were characterised by optical spectroscopy. The structures grown on silicon resulted in the first observation of SC in transmission measurements for III-nitrides. High quality factors were observed from MCs grown on FS-GaN and on GaN-on-sapphire templates. These approaches open the way to improved structural quality of the active region, resulting from the use of substrates with low TDD.